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At least 19 recordsLinked to original sources

PubMed2026

Fault-tolerant pedigree reconstruction from pairwise kinship relations.

MOTIVATION: Pedigrees reconstructed from biologically related ancient genomes have revealed many insights into (pre)history. To our knowledge, all reported ancient pedigrees have been primarily manually reconstructed, as existing pedigree reconstruction methods are ill-suited for the quality and nature of ancient DNA data. RESULTS: We introduce repare, an open-source software method to automatically reconstruct pedigrees from inferred pairwise kinship relations, which are readily obtainable from ancient genomes. This method reconstructs pedigrees by iteratively incorporating pairwise kinship relations into a set of candidate pedigrees, with pruning and sampling to reduce its search space. It optionally considers supporting information such as haplogroups and skeletal age-at-death estimates. We evaluate this method on a variety of simulated pedigrees with varying error rates and missingness. We also use this method to reconstruct several published pedigrees that were originally manually reconstructed; for one, we present a potential alternative topology. repare optionally incorporates user-inferred pedigree constraints, enabling "human-in-the-loop" reconstruction workflows. Especially when used with these user-inferred constraints, we find that repare represents a powerful and flexible tool for ancient pedigree reconstruction. AVAILABILITY AND IMPLEMENTATION: repare is freely available at https://github.com/Narasimhan-Lab/repare. In addition, source code, benchmark scripts, and benchmark results used in this work are archived at https://doi.org/10.5281/zenodo.19716772.

Pedigree↗

PubMed2026

X chromosome-wide association studies for quantitative trait loci based on the mixture of general pedigrees and additional unrelated individuals.

Genome-wide association studies have successfully identified many genetic variants associated with complex traits. However, most existing methods target autosomes rather than X chromosome, and several existing X chromosome-wide association studies (XWAS) at quantitative trait loci (QTL) largely focus on unrelated individuals, with limited attention to general pedigrees or mixture of general pedigrees and additional unrelated individuals (called the mixed data for brevity). In this study, we propose nine novel methods for XWAS at QTL in the mixed data (${\mathrm{MQX}}_{\mathrm{cat}}$, ${\mathrm{MQZ}}_{\mathrm{max}}$, ${\mathrm{MT}}_{\mathrm{plinkw}}$, ${\mathrm{MT}}_{\mathrm{chenw}}$, $\mathrm{MwM}3\mathrm{VNA}$, ${\mathrm{MQMVX}}_{\mathrm{cat}}$, ${\mathrm{MQMVZ}}_{\mathrm{max}}$, $\mathrm{MpMV}$, and $\mathrm{McMV}$), also applicable to general pedigrees alone. The first four methods test for mean differences across genotypes; the latter four test for differences in both means and variances; $\mathrm{MwM}3\mathrm{VNA}$ tests for variance differences only. All mean-based and mean-variance-based methods incorporate X chromosome inactivation information, and all nine methods consider genetic relatedness in pedigrees. Simulation studies confirm well-controlled type I error rates, and inclusion of pedigrees significantly improves statistical power. Note that there has been no study focusing on X chromosome for the mixed data or general pedigrees from UK Biobank database, so we apply our proposed methods to this dataset, which identify five total cholesterol (TC)-associated and 13 low-density lipoprotein cholesterol (LDL-C)-associated single nucleotide polymorphisms (SNPs). Linkage disequilibrium (LD) analysis reveals that these SNPs fall into three distinct LD blocks. Functional annotation and gene ontology enrichment analysis reveal 16 and 28 enriched pathways for TC-associated and LDL-C-associated genes, respectively. These methods provide robust and powerful tools for XWAS at QTL in both mixed data and general pedigrees.

Quantitative Trait Loci↗

PubMed2026

[Pathogenicity analysis and prenatal genetic counseling for five Chinese pedigrees harboring a hemizygous c.-32C>G variant of FGF13 gene].

OBJECTIVE: To explore the pathogenicity and prenatal counseling strategies for five Chinese pedigrees harboring a hemizygous c.-32C>G (NM_001139500.2) variant of fibroblast growth factor 13 (FGF13) gene. METHODS: Five Chinese pedigrees found to carry a hemizygous c.-32C>G variant of the FGF13 gene at the Prenatal Diagnosis Center of Henan Provincial People's Hospital between January 2024 and January 2025 were selected as study subjects. The pedigrees had undergone prenatal diagnosis for a family history of genetic disorders, abnormal fetal ultrasound findings, or advanced maternal age. A retrospective analysis was carried out, wherein clinical data for all members of the pedigrees were obtained through the medical records system and outpatient visit system. Peripheral blood samples were collected from all pedigree members, and amniotic fluid samples were obtained from the probands. Following extraction of genomic DNA, prenatal diagnosis was performed using chromosomal microarray analysis (CMA) and trio whole-exome sequencing (trio-WES). Sanger sequencing was used to determine the carrier status for the candidate variant, and Mini-Mental State Examination (MMSE) was used to assess the cognitive function of hemizygous individuals carrying the FGF13 gene c.-32C>G variant. Pathogenicity of candidate variant was assessed based on guidelines from the American College of Medical Genetics and Genomics (ACMG). This study was approved by the Medical Ethics Committee of the hospital (Ethics No.: 2021-171). RESULTS: CMA and trio-WES revealed no pathogenic variants in all probands, whilst trio-WES and Sanger sequencing had identified 11 male individuals carrying a hemizygous c.-32C>G variant of the FGF13 gene from the five pedigrees, which included six adult males, a young boy, and four fetuses. One fetus had undergone termination of pregnancy due to hydrocephalus, one was born pre-term at 34+1 weeks of gestation owing to maternal hypertension, and other two were delivered at full term. Follow-up of the survived males revealed no phenotypic manifestations related to language or intellectual impairment. Among these, three adult males underwent the MMSE assessment, all of whom showed normal cognitive function. Search of the gnomAD database suggested the carrier frequency of FGF13 c.-32C>G variant in the East Asian population to be 0.125%, with 11 hemizygous males documented. Three male patients harboring the variant showed severe intellectual disability. Both in vitro and in vivo studies suggested that it could reduce the translation levels of FGF13 protein. Based on the ACMG guidelines, it was classified as variant of uncertain significance (BS4+PS3_Supporting). CONCLUSION: There is insufficient evidence to classify the FGF13 c.-32C>G as a pathogenic variant in clinical practice, and its presence should not be considered an indication for pregnancy termination due to major birth defects.

Adult↗

PubMed2026

Pedigree-assisted genotype imputation enables cost-effective genomic prediction in Penaeus vannamei.

Genomic selection in Penaeus vannamei has long been constrained by the high cost of dense genotyping. To address this limitation, we evaluated genotype imputation from a low-density 1 K panel to a medium-density 55 K panel of the "Yellow Sea Array No. 1" and examined its impact on genomic prediction for harvest body weight in P. vannamei. A four-generation pedigree including 30 great-grandparents, 39 grandparents, 100 parents, and 608 offspring was genotyped using the 55 K panel. A two-step experimental design was implemented to (i) assess the performance of different imputation algorithms under reference population scenarios with varying proportions of siblings, and (ii) compare six alternative reference population structures incorporating parents, ancestors, and siblings. Genotype imputation using the pedigree-based method FImpute v3.0 consistently achieved higher accuracy than the population-based method Beagle v5.5. Using this pedigree-assisted approach, imputation accuracy increased from 0.73 when only parental genotypes were used to 0.84 with the inclusion of 10% siblings, and subsequently plateaued at 0.87-0.90 when sibling representation reached 20%. Across the six reference population structures, imputation accuracy was primarily driven by the availability of parental genotypes, ranging from 0.50 to 0.56 in the absence of parents to 0.88-0.89 when both parents and ancestral generations were included. Accuracy remained high when both parents were available (0.84-0.87 with siblings; 0.73 without siblings) but declined substantially when only one parent was genotyped (0.65-0.68). Imputation accuracy was positively associated with both minor allele frequency (MAF) and linkage disequilibrium (max r2LD), with LD exerting the stronger influence. Heritability estimates derived from imputed 55 K genotypes were highly consistent with those obtained from the original 55 K data (0.39 ± 0.14 vs. 0.41 ± 0.14), indicating that genotype imputation did not compromise variance component estimation. In predictive ability analyses, pedigree-based BLUP (PBLUP) achieved higher predictive ability than genomic BLUP (GBLUP) based on the 1 K panel, with predictive abilities of 0.42-0.44 for PBLUP compared with 0.34-0.35 for GBLUP. Using imputed genotypes for genomic prediction further improved predictive ability relative to the true 1 K panel, yielding values ranging from 0.35 to 0.47. Notably, when parental genotypes were included in the reference population, GBLUP based on imputed genotypes surpassed the predictive ability of PBLUP and approached that achieved with the original 55 K genotypes (0.45-0.47). Collectively, these results provide the first empirical evidence that low- to medium-density genotype imputation, combined with pedigree information, can effectively support genomic prediction in P. vannamei. This study establishes a cost-efficient and scalable framework for implementing genomic selection in P. vannamei and provides a practical reference for the application of genomic selection in other aquaculture species with constrained breeding budgets.

Animals↗

PubMed2025

Whole-exome sequencing uncovers the genetic basis of hereditary concomitant exotropia in ten Chinese pedigrees.

PURPOSE: To explore possible pathogenic genes for concomitant exotropia using whole-exome sequencing. METHODS: In this study, 47 individuals from 10 concomitant exotropia (including intermittent exotropia and constant exotropia) pedigrees were enrolled. Whole-exome sequencing was used to screen mutational profiles in 25 affected individuals and 10 unaffected individuals. Sanger sequencing and in silico analysis were performed for all participants. Two target genes were used to capture the sequences of 220 sporadic samples. RESULTS: All 10 concomitant exotropia pedigrees presented autosomal dominant inheritance with childhood onset (3.35 ± 1.51 years old). Eleven different missense variants were identified among seven potential pathogenic genes (COL4A2, SYNE1, LOXHD1, AUTS2, GTDC2, HERC2 and CDH3) that cosegregated with pedigree members. All variants were predicted to be deleterious and had low frequencies in the general population. Distinct variants of COL4A2 were present in three pedigrees, and distinct variants of SYNE1 were present in two pedigrees. Fifteen variants in AUTS2 and four variants in GTDC2 were identified in 220 patients with sporadic concomitant exotropia using a target-capture sequencing approach. CONCLUSION: This is the first study to explore the genetic mechanism of concomitant exotropia and identify seven associated genes (COL4A2, SYNE1, LOXHD1, AUTS2, GTDC2, HERC2 and CDH3) that may be candidate genes causing concomitant exotropia. More samples and in-depth studies are needed to verify these findings.

Adult↗

PubMed2024

BICEP: Bayesian inference for rare genomic variant causality evaluation in pedigrees.

Next-generation sequencing is widely applied to the investigation of pedigree data for gene discovery. However, identifying plausible disease-causing variants within a robust statistical framework is challenging. Here, we introduce BICEP: a Bayesian inference tool for rare variant causality evaluation in pedigree-based cohorts. BICEP calculates the posterior odds that a genomic variant is causal for a phenotype based on the variant cosegregation as well as a priori evidence such as deleteriousness and functional consequence. BICEP can correctly identify causal variants for phenotypes with both Mendelian and complex genetic architectures, outperforming existing methodologies. Additionally, BICEP can correctly down-weight common variants that are unlikely to be involved in phenotypic liability in the context of a pedigree, even if they have reasonable cosegregation patterns. The output metrics from BICEP allow for the quantitative comparison of variant causality within and across pedigrees, which is not possible with existing approaches.

Pedigree↗

PubMed2026

Combinatorial multiomic analysis from a pedigree of Sox10Dom Hirschsprung mice identifies multiple high confidence candidate modifiers of Enteric Nervous System development.

Hirschsprung disease (HSCR) is characterized by absence of enteric ganglia (aganglionosis) along variable lengths of the distal intestine. This disorder results from deficient colonization of fetal intestine by enteric neural crest-derived cells (ENCDCs). HSCR exhibits complex, multifactorial inheritance with penetrance and severity varying widely even within families. SOX10 is among causal genes that predispose to aganglionosis. Yet, how gene interactions influence severity of HSCR aganglionosis is not understood. Prior mapping of aganglionosis modifiers was achieved in a standard F1-intercross utilizing the Sox10Dom HSCR mouse model. Here we deploy a novel strategy of genotyping an extended pedigree pedigree of Sox10Dom mice on a mixed genetic background. GWAS in this pedigree points to novel aganglionosis modifier intervals with replication and refinement of prior modifier regions. Complementary omics analysis of the developing Enteric Nervous System (ENS) enabled identification of multiple high-priority candidate genes within these modifier intervals based on gene expression, chromatin accessibility, and presence of conserved SOX10 binding motifs. We implemented a prioritization pipeline for ranking potential modifiers that generated candidate lists including several well-known for effects on ENS development as well as multiple novel genes. Among the novel genes, Dach1 ranked as a top priority candidate gene for modifying migration of ENCDCs and thus influencing aganglionosis severity. The results identify genome intervals with intrinsic genes that are logical candidates for modifying Sox10Dom aganglionosis severity. We also note that several human orthologs to aganglionosis modifier candidate genes are within linkage disequilibrium blocks containing genetic variants associated with human gut motility disorders, which offers opportunity for gaining biological insight into human HSCR severity.

Animals↗

PubMed2026

[Analysis of clinical phenotypes and pathogenicity of a c.4476+5G>T variant of SCN1A gene in a Chinese pedigree affected with Genetic epilepsy with febrile seizures plus].

OBJECTIVE: To explore the pathogenicity and characteristics of a heterozygous splicing variant of SCN1A gene in a Chinese pedigree affected with Genetic epilepsy with febrile seizures plus (GEFS+). METHODS: A retrospective analysis was carried out on the clinical data and results of genetic testing of a GEFS+ pedigree consisting of 5 members who had visited the First Affiliated Hospital of Zhengzhou University on July 1, 2024. Pathogenicity of the splicing variant of the SCN1A gene was validated with a minigene splicing assay. This study was approved by the Medical Ethics Committee of the the First Affiliated Hospital of Zhengzhou University (Ethics No.: KS-2018-KY-36). RESULTS: The proband, a 24-year-old female, presented with FS in conjunct with focal seizures, and both of her younger brothers had Dravet syndrome. All of the three patients had carried a c.4476+5G>T variant of the SCN1A gene, which was unreported previously. Minigene experiment verified that the variant could cause loss of the first 7 bps of exon 24 and 138 bps from exon 23 of the SCN1A gene, resulting in alteration p.V1447_1495delfs*6 and affecting splicing. Based on the guidelines from American College of Medical Genetics and Genomics (ACMG), the variant was predicted as likely pathogenic (PVS1+PM2_Supporting). CONCLUSION: The c.4476+5G>T variant at an intronic site of the SCN1A gene probably underlay the pathogenesis of GEFS+ in this pedigree.

Adult↗

PubMed2026

A Case Report of a Pedigree with Distal Hereditary Motor Neuropathy Caused by a Homozygous c.1124G>A Variant an the /*9Vaccinia-Related Kinase 1 Gene.

This study aimed to analyze the clinical phenotypes, neurophysiological characteristics, and pathogenicity of gene variants in a pedigree with distal hereditary motor neuropathy (dHMN) caused by VRK1 variants, and to provide evidence to support clinical diagnosis and genetic counseling for this disease. We report a Chinese consanguineous family with dHMN caused by a homozygous c.1124G>A variant in the VRK1 gene. Clinical and electrophysiological data of the proband were collected. Whole-exome sequencing (WES) and validation by Sanger sequencing were performed to identify the variant site, and pathogenicity interpretation was conducted in accordance with American College of Medical Genetics and Genomics/Association for Molecular Pathology (ACMG/AMP) guidelines. The proband was a 24-year-old male who presented with 2 years of progressive weakness and atrophy of the distal lower limbs, accompanied by slender upper limbs and no sensory disturbance. Electrophysiological examination showed decreased compound muscle action potential (CMAP) amplitude in motor nerves of both upper and lower limbs, indicating peripheral neurogenic damage, while sensory nerve conduction was normal. Genetic testing detected a homozygous c.1124G>A (p.Trp375Ter) variant in the VRK1 gene. His parents and elder sisters were heterozygous carriers, and the pedigree conformed to autosomal recessive inheritance. According to ACMG guidelines, this variant was classified as pathogenic (evidence: PVS1, PM2, PP1). The homozygous VRK1 c.1124G>A variant causes adult-onset dHMN, rather than pontocerebellar hypoplasia type 1A (PCH1A) as annotated in some genetic databases. This pedigree presents distinctive phenotypes, including slender upper limbs and diffusely decreased CMAP amplitudes in both upper and lower limbs, thereby expanding the clinical and genetic spectrum of VRK1-related dHMN in the Chinese population.

Humans↗

PubMed2026

Compound Heterozygous PCDH15 Variants Associated With Cone-Rod Dystrophy in a Chinese Pedigree.

BACKGROUND: This study aimed to characterize the clinical and genetic features of a Chinese family with cone-rod dystrophy in which compound heterozygous PCDH15 variants were identified. METHODS: A Chinese pedigree with autosomal recessive cone-rod dystrophy was investigated. A comprehensive ophthalmic assessment was performed in the proband, a 42-year-old woman, together with genetic evaluation of her family members. Candidate variants were identified using whole-exome sequencing and subsequently assessed by Sanger sequencing and family segregation analysis. RESULTS: Ophthalmoscopic examination revealed pigmentary changes and atrophic lesions affecting the posterior pole and peripapillary area bilaterally. Optical coherence tomography (OCT) demonstrated bilateral outer retinal layer atrophy with disruption of the ellipsoid zone at the posterior pole. Multifocal electroretinography (mfERG) revealed attenuated central responses, while full-field electroretinography (ffERG) documented a more pronounced reduction in cone-mediated (photopic) responses. Two novel compound heterozygous variants in PCDH15, namely c.4903_4906del (p.Glu1635Lysfs*4) and c.3470C>A (p.Ala1157Glu), were identified in this autosomal recessive cone-rod dystrophy pedigree. Family co-segregation analysis provided supportive evidence for their potential association with the disease phenotype. Cross-species analysis revealed high evolutionary conservation of the PCDH15 protein. Three-dimensional structural modeling predicted potential alterations in protein structure. CONCLUSION: To our knowledge, this is the first report describing an association between compound heterozygous PCDH15 variants and cone-rod dystrophy, thereby providing preliminary evidence that may broaden the mutational spectrum associated with this gene.

Adult↗

PubMed2024

SLC40A1-related hemochromatosis associated with a p.Y333H mutation in mainland China: a pedigree report and literature review.

BACKGROUND: Haemochromatosis is a genetic disease characterized by the excessive deposition of iron in various tissues and organs, eventually results in organ damage including cirrhosis, diabetes, cardiomyopathy, etc. SLC40A1-related haemochromatosis is associated with gain-of-function mutations in the SLC40A1 gene, which encodes ferroportin. While sporadic reports of this condition exist in mainland China, the understanding of the phenotype and genetic pattern associated with the SLC40A1 p.Y333H mutation remains incomplete. CASE PRESENTATION: We report a pedigree with heterozygous p.Y333H mutation in Chinese Han population. The proband is a 64-year-old man complaining of persistent abnormality of liver enzyme levels for 1 year, with a history of knee joint pain, diabetes and skin pigmentation. He displayed markedly elevated serum ferritin level and transferrin saturation. Magnetic resonance imaging showed iron deposition in the liver, spleen, and pancreas, along with cirrhosis and splenomegaly. Whole exome sequencing identified a heterozygous allelic variant c.997T > C (p.Y333H). Genetic screening of family members identified four first-degree relatives and three second-degree relatives having the same mutation. Additional cases with this mutation from two published studies were included. Among the probands and screened relatives, all eight males aged over 30 y had ferritin level > 1000 µg/L, transferrin saturation > 90%. Four patients with organ damage in the present study received therapeutic phlebotomy, alleviating clinical symptoms and improving in transferrin saturation and serum ferritin. CONCLUSIONS: This study reports the largest pedigree with heterozygous SLC40A1 p.Y333H mutation in the Chinese population to date. In Chinese families, males over 30 years old with hemochromatosis due to SLC40A1 p.Y333H mutation exhibit severe iron overload phenotypes.

Humans↗

PubMed2026

Microsatellites Versus Genome-Wide SNPs Data for Pedigree Reconstruction in Twin Simmental Crossbred Cattle.

Accurate pedigree reconstruction is critical for genetic evaluation in admixed cattle populations, yet the relative performance of microsatellite and genome-wide SNP markers in twin-rich herds with incomplete pedigree records remains unclear. We compared 12 ISAG-recommended microsatellite markers with whole-genome SNP data for dam-calf assignment in a Simmental crossbred population (n = 43, 13 dam-calf groups) from southern China. Twin zygosity was determined from SNP identity-by-descent (PI_HAT) values: nine calf pairs were dizygotic, one pair was monozygotic (20A/21A), and one adult pair was composed of dizygotic twin sisters (31A/34A). Admixture analysis at K = 3 revealed ancestry proportions of 50.7% European taurine, 28.9% Chinese indicine and 20.4% East Asian taurine. The SNP-based neighbor-joining tree correctly recovered 12 of 13 groups (92.3%, 95% CI: 64.0-99.8%), whereas the microsatellite-based tree recovered 11 (84.6%, 95% CI: 54.6-98.1%); the difference was not statistically significant (exact McNemar test, p = 1.0). Locus INRA023 was monomorphic (PIC = 0), reducing the effective number of markers to 11. These results indicate that genome-wide SNPs show a favourable trend in accuracy and are less prone to false-positive clustering than a standard microsatellite panel in admixed, twin-rich cattle populations.

SNP↗

PubMed2026

[Genetic and functional characterization of a novel KIT splicing variant in a Chinese three-generation pedigree with piebaldism].

OBJECTIVES: To investigate the genetic etiology of a three-generation pedigree affected with piebaldism. METHODS: Next-generation sequencing and Sanger sequencing were employed to detect and verify gene variants. Bioinformatics tools were used to predict the effects of candidate variants on splicing and protein function. RT-PCR and Sanger sequencing were further performed to validate the impact of the variant on RNA splicing, and homology modeling was applied to predict its effect on the three-dimensional structure of the KIT protein. The pathogenicity of the variant was then classified according to the guidelines of the American College of Medical Genetics and Genomics (ACMG) and the UK Association for Clinical Genomic Science (ACGS). RESULTS: A heterozygous insertion variant near the splice site, c.1990+8_1990+9insTGCACCATTGGAGGTAAA, was identified in the KIT gene in the proband and was found to co-segregate with the phenotype within the family. RT-PCR and cDNA sequencing revealed that this variant led to aberrant splicing during transcription, resulting in a 21 bp in-frame insertion in the mRNA, which encodes an extra 7 amino acids within the tyrosine kinase domain and may thus affect protein function. In silico predictions, together with the experimental findings, supported classification of this variant as likely pathogenic according to relevant variant interpretation guidelines. CONCLUSIONS: The heterozygous splice-site insertion variant KIT:c.1990+8_1990+9insTGCACCATTGGAGGTAAA is the genetic cause of piebaldism in this pedigree.

Genetics diagnosis↗

PubMed2025

Pedigree analysis and genetic inheritance of fatal familial insomnia (FFI) in a Portuguese multigenerational family.

Fatal familial insomnia (FFI) is a rare, autosomal dominant prion disease caused by a mutation in the PRNP gene, leading to the misfolding of the cellular prion protein (PrPC) into its pathogenic form (PrPSc). This results in neurodegeneration, particularly in the thalamus, a key region regulating sleep-wake cycles, which underlies the hallmark symptoms of FFI, including insomnia, autonomic dysfunctions, motor disturbances and cognitive decline. This study focuses on a Portuguese family with FFI, providing a detailed pedigree analysis spanning five generations and comprising 134 individuals, to elucidate inheritance patterns, disease onset, and clinical progression. The findings confirm the autosomal-dominant inheritance pattern and a strong familial clustering of the disease with age of onset in the late 50s (mean 57 years). Although 67% of affected individuals succumbing to the disease within months to 1.5 years, a notably 33% exhibited prolonged survival beyond the typical disease duration, exceeding proportions reported in the literature. Family members retrospectively reported prodromal symptoms, including generalized pain, headaches, tinnitus, pruritus, and behavioral changes, occurring up to five years before diagnosis. In several cases, reportedly, disease onset was associated with major phycological stressors (e.g., emotional stress or mourning). While the significance of these observations remains uncertain, they may provide insights into potential early features in this kindred. Further research integrating genomic sequencing, biomarkers, and longitudinal clinical assessments are needed to better understand the mechanisms underlying the heterogeneity of FFI and to explore potential therapeutic interventions.

Humans↗

PubMed2001

Linkage analysis of a complex pedigree with severe bipolar disorder, using a Markov chain Monte Carlo method.

Recently developed algorithms permit nonparametric linkage analysis of large, complex pedigrees with multiple inbreeding loops. We have used one such algorithm, implemented in the package SimWalk2, to reanalyze previously published genome-screen data from a Costa Rican kindred segregating for severe bipolar disorder. Our results are consistent with previous linkage findings on chromosome 18 and suggest a new locus on chromosome 5 that was not identified using traditional linkage analysis.

Algorithms↗

PubMed2026

Scalable medium-density genotyping platforms for cultivar identification, pedigree authentication, marker-assisted and genomic selection, and other applications in strawberry.

A broad spectrum of high-density genotyping approaches, including single-nucleotide polymorphism (SNP) arrays, genotyping-by-sequencing, and whole-genome reduced-representation sequencing, have been shown to perform well in strawberry (Fragaria × ananassa), despite the inherent complexity of the octoploid genome. While these approaches are effective, their routine deployment in breeding programs can be constrained by cost, computational requirements, and workflow complexity. In parallel, many breeding programs continue to rely on locus-specific assays for marker-assisted selection, resulting in fragmented and inefficient genotyping strategies. Here, we describe medium-density amplicon-based genotyping platforms for strawberry designed to provide cost-effective, turnkey solutions that integrate markers used for marker-assisted selection with genome-wide markers suitable for genomic prediction in a single laboratory assay. These platforms were developed by targeting 1,650 or 4,811 target SNPs via amplicon sequencing, and are interoperable with existing high-density genotyping resources, including a widely used 50K SNP array, thereby facilitating data integration across platforms. We benchmarked their performance relative to the 50K SNP array across breeding-relevant applications, including identity and purity testing, pedigree authentication, marker-assisted selection, and genomic selection, and further evaluated the feasibility of genotype imputation to enhance genome-wide information content. Across analyses, the 1,650- and 4,811-amplicon platforms produced results comparable to higher-density platforms while substantially reducing genotyping cost and analytical overhead. This work demonstrates that targeted amplicon-based genotyping can support efficient, scalable, and integrated genome-informed breeding, enabling the routine application of both marker-assisted and genomic selection within strawberry breeding workflows. Open-source R workflows are provided to support streamlined analyses in breeding contexts.

Fragaria↗

PubMed2025

AVITI sequencing of a four-generation CEPH/Utah pedigree confirms low mutation rates at homopolymer loci despite their low sequence complexity.

BACKGROUND: Short tandem repeats (STRs) and homopolymers are among the most mutable loci in the human genome. Despite their presumed mutability owing to replication slippage, homopolymer loci exhibit lower mutation rates and minimal paternal age effects compared to other STRs. This paradox questions if technical limitations, rather than biological mechanisms, explain these observations. RESULTS: We used the Element Biosciences AVITI platform to sequence the genomes of a 48-member, four-generation CEPH/Utah pedigree. As the AVITI platform reduces error rates at repetitive sequences compared to Illumina, this design enabled accurate mutation discovery at 90% of assayed homopolymers and a 1.7-fold increase in discoverable mutations compared to Illumina. We identified a median of 35 de novo homopolymer mutations per trio and a mutation rate of 5.28 × 10-5 DNMs per locus per generation, confirming a lower rate than dinucleotides (1.94 × 10-4). Most DNMs were single base-pair expansions or contractions. Despite comprising <1% of homopolymer loci, G/C homopolymers showed 18-fold higher mutation rates than A/T homopolymers; in contrast, the high dinucleotide mutation rate is not driven by a particular motif class. Parent-of-origin analysis revealed 78% of homopolymer mutations are paternal in origin, but no significant paternal age effect was observed. CONCLUSIONS: This study confirms that homopolymers exhibit lower mutation rates and lack strong paternal age effects compared to other STRs, likely owing to the combination of a lower propensity to form slippage-causing secondary structures and more efficient mismatch repair. Our set of high-quality mutations suggest these phenomena are biological rather than technical in nature. Finally, we demonstrate that AVITI sequencing unlocks previously intractable regions of the genome and will be a powerful tool for continued investigation of repeat mutation.

AVITI↗

PubMed2026

Xp21 contiguous gene deletion syndrome presenting as congenital adrenal hypoplasia: molecular diagnosis and clinical re-evaluation of a pedigree.

OBJECTIVE: To investigate the molecular etiology in a male child clinically suspected of congenital adrenal hyperplasia (CAH) with negative conventional genetic testing, and to elucidate the genetic characteristics of his pedigree. METHODS: Clinical data from the proband and his family members were collected. Molecular diagnostics proceeded sequentially: initial targeted CAH testing (CYP21A2 and POR sequencing/MLPA, plus targeted NR0B1 CNV analysis) was followed by whole-exome sequencing coupled with genome-wide CNV analysis. RESULTS: The proband presented with neonatal cyanosis and hyperpigmentation. Laboratory tests showed markedly elevated ACTH (354.68 pmol/L) and low aldosterone (57.24 pg/mL). Molecular genetic testing identified a hemizygous deletion of approximately 4.44 Mb at Xp21.3-p21.1 (chrX:g.27080000_31520000), encompassing the NR0B1, GK, IL1RAPL1, and DMD genes. CNV-seq confirmed that the mother carried a heterozygous deletion of 4.38 Mb in the same region, while the father and four maternal aunts showed normal genotypes. CONCLUSION: This study ultimately diagnosed the proband with Xp21 contiguous gene deletion syndrome. The adrenal insufficiency resulted from X-linked congenital adrenal hypoplasia (AHC) due to NR0B1 haploinsufficiency, rather than CAH. These findings highlight the considerable clinical overlap between AHC and CAH, indicating that CNV analysis of the Xp21 region should be included in the diagnostic workup for male infants with suspected CAH but negative routine genetic testing. This provides a basis for the precise diagnosis and genetic counseling of such patients.

Humans↗