Biomedical subjects

Sigrid Tinschert

Publications and source records attributed to Sigrid Tinschert.

At least 19 recordsLinked to original sources

PubMed2006

Compound heterozygosity for two MSH6 mutations in a patient with early onset of HNPCC-associated cancers, but without hematological malignancy and brain tumor.

Heterozygous germline mutations in the human mismatch repair (MMR) genes MLH1, PMS2, MSH2 and MSH6 predispose to the hereditary non-polyposis colorectal cancer (HNPCC) syndrome. Biallelic mutations in these genes have been reported for a limited number of cases resulting in hematological malignancies, brain tumors and gastrointestinal tumors early in childhood. These tumor phenotypes are frequently associated with café-au-lait spots (CALS), one of the clinical hallmarks of neurofibromatosis type 1 (NF1). We report the first case of compound heterozygosity for two MSH6 mutations resulting in a nonconservative amino-acid change of a conserved residue and in a premature stop codon in a patient who developed rectal and endometrial cancer at ages 19 and 24 years, respectively, and presented few CALS in a single body segment. Immunohistochemistry and Western blotting revealed only residual expression of the MSH6 protein in the normal cells. The disease history resembles the HNPCC phenotype rather than a phenotype associated with biallelic MMR gene mutations. Therefore, we assume that one or both mutations abolish protein function only partially, further supported by the parents, which are both carriers of one of the mutations each, and not affected by the disease at ages 57 and 58 years. Our data suggest considering biallelic mutations in MMR genes for patients who develop HNPCC-associated tumors at an unusually young age of onset, even without hematological or brain malignancies.

Adult↗

PubMed2005

Shprintzen-Goldberg syndrome: fourteen new patients and a clinical analysis.

The Shprintzen-Goldberg syndrome (SGS) is a disorder of unknown cause comprising craniosynostosis, a marfanoid habitus and skeletal, neurological, cardiovascular, and connective-tissue anomalies. There are no pathognomonic signs of SGS and diagnosis depends on recognition of a characteristic combination of anomalies. Here, we describe 14 persons with SGS and compare their clinical findings with those of 23 previously reported individuals, including two families with more than one affected individual. Our analysis suggests that there is a characteristic facial appearance, with more than two thirds of all individuals having hypertelorism, down-slanting palpebral fissures, a high-arched palate, micrognathia, and apparently low-set and posteriorly rotated ears. Other commonly reported manifestations include hypotonia in at least the neonatal period, developmental delay, and inguinal or umbilical hernia. The degree of reported intellectual impairment ranges from mild to severe. The most common skeletal manifestations in SGS were arachnodactyly, pectus deformity, camptodactyly, scoliosis, and joint hypermobility. None of the skeletal signs alone is specific for SGS. Our study includes 14 mainly German individuals with SGS evaluated over a period of 10 years. Given that only 23 other persons with SGS have been reported to date worldwide, we suggest that SGS may be more common than previously assumed.

Abnormalities, Multiple↗

PubMed2005

Twenty-six novel EFNB1 mutations in familial and sporadic craniofrontonasal syndrome (CFNS).

Craniofrontonasal syndrome (CFNS) is an X-linked disorder characterized by a more severe manifestation in heterozygous females than in hemizygous males. Heterozygous females have craniofrontonasal dysplasia (CFND) and occasionally extracranial manifestations including midline defects and skeletal abnormalities, whereas hemizygous males show no or only mild features such as hypertelorism and rarely show cleft lip or palate. Mutations in the EFNB1 gene in Xq12 are responsible for familial and sporadic CFNS. The EFNB1 gene encodes ephrin-B1, a transmembrane ligand that also exhibits receptor-like effects. We performed mutation analysis in nine unrelated families and 29 sporadic patients with CFNS. DNA sequencing revealed mutations in 33 (86.8%) cases including 26 distinct novel mutations. A recurrent nonsense mutation, c.196C>T/R66X, was detected in one family and four sporadic patients. The majority of mutations (26/33) were located in exons 2 and 3 of the EFNB1 gene encoding the extracellular ephrin domain. The mutation spectrum includes frameshift, nonsense, missense, and splice site mutations, with a predominance of frameshift and nonsense mutations resulting in premature truncation codons. For the first time we describe mutations in exons 4 and 5 of EFNB1. Of particular interest are the frameshift mutations located in the last 25 codons of EFNB1 encoding the carboxyterminal end of ephrin-B1. They result in an extension by 44 residues. These mutations disrupt the intracellular binding sites for Grb4 and PDZ-effector proteins involved in reverse signaling. We conclude that the major causes of familial as well as sporadic CFNS are loss of function mutations in the EFNB1 gene that comprise premature termination or abrogate receptor-ligand interaction, oligomerization, and ephrin-B1 reverse signaling.

Amino Acid Sequence↗

PubMed2005

Novel mutations in BCOR in three patients with oculo-facio-cardio-dental syndrome, but none in Lenz microphthalmia syndrome.

Oculo-facio-cardio-dental (OFCD) syndrome is a rare X-linked dominant condition with male lethality characterized by microphthalmia, congenital cataracts, facial dysmorphic features, congenital heart defects, and dental anomalies. Mutations in BCOR (BCL6 co-repressor) located in Xp11.4 have been described to cause OFCD syndrome. Lenz microphthalmia syndrome is inherited in an X-linked recessive pattern comprising microphthalmia/anophthalmia, mental retardation, malformed ears, digital, skeletal, and urogenital anomalies (synonym: microphthalmia with associated anomalies (MAA)). One locus for MAA has been mapped to Xq27-q28. Nonetheless, linkage and subsequent mutation analysis revealed a single missense mutation (p.P85L) in BCOR in a large family with presumed Lenz microphthalmia syndrome (MAA2). We describe novel mutations in BCOR in three patients with OFCD syndrome, two small deletions (c.2488_2489delAG and c.3286delG) and a submicroscopic deletion of about 60 kb encompassing at least BCOR exons 2-15. No BCOR mutation was detected in eight patients with Lenz microphthalmia syndrome. Our data confirm that BCOR is the causative gene for OFCD syndrome; however, the failure to identify any mutation in patients with Lenz microphthalmia syndrome together with the oligosymptomatic phenotype in the reported MAA2 patients suggest that BCOR is not the major gene for this syndrome.

Abnormalities, Multiple↗

PubMed2005

Childhood overgrowth in patients with common NF1 microdeletions.

While growth retardation and short stature are well-known features of patients with classical neurofibromatosis type 1 (NF1), we found advanced height growth and accelerated carpal bone age in patients with an NF1 microdeletion. Our analysis is based on growth data of 21 patients with common 1.4/1.2 Mb microdeletions, including three patients with a Weaver-like appearance. Overgrowth was most evident in preschool children (2-6 years, n=10, P=0.02). We conclude that childhood overgrowth is part of the phenotypic spectrum in patients with the common 1.4/1.2 Mb NF1 microdeletions and assume that the chromosomal region comprised by the microdeletions contains a gene whose haploinsufficiency causes overgrowth.

Adolescent↗

PubMed2004

Macrocephalic mental retardation associated with a novel C-terminal MECP2 frameshift deletion.

UNLABELLED: We report a novel C-terminal MECP2 frameshift deletion (1135_1142delCCCGTG CC) in a 19-year-old woman with mental retardation and epilepsy. Preservation of language capabilities, purposeful hand use and sufficient locomotion implied an atypical variant of Rett syndrome (OMIM 312750). Occipito-frontal head circumference was large at birth (36 cm; SDS 1.7) and increased until adulthood (58.5 cm; SDS 2.3). CONCLUSION: Our observation indicates that head size and head growth are of limited reliability in the diagnosis of MECP2-associated phenotypes.

Adult↗

PubMed2004

Dyschromatosis universalis hereditaria: familial case and ultrastructural skin investigation.

We report a familial case of dyschromatosis universalis hereditaria (DUH) which is compatible with an autosomal dominant inheritance. The male proband from Bangladesh presented with randomly distributed hyper- and hypo-pigmented skin lesions of variable shape and size with a mottled appearance. Three additional members of the non-consangineous family are similarly affected. Light and electron microscopy show normal numbers of active melanocytes, but different amounts of fully melanized melanosomes in hyper-pigmented and hypo-pigmented macules. Our findings indicate that DUH is not a disorder of number. It appears to be a disorder of melanosome synthesis rate or in addition melanocyte activity.

Adult↗

PubMed2004

Screening 500 unselected neurofibromatosis 1 patients for deletions of the NF1 gene.

A total of 500 unselected unrelated neurofibromatosis 1 (NF1) patients were screened for deletions of the NF1 gene. After excluding 67 patients with known intragenic NF1 mutations, the remaining 433 were genotyped using six intragenic and one distal microsatellite marker for the NF1 gene. A total of 28 patients were hemi- or homozygous for all seven markers and were thus considered as candidates for NF1 deletion with a calculated probability of 99.99%. Metaphase or interphase cells were available from 23 of these 28 individuals for molecular cytogenetics. Fluorescence in situ hybridization (FISH) confirmed an NF1 deletion in 22 (96%) of the 23 patients. Thus, a constitutional deletion of the NF1 gene is responsible for the disease phenotype in at least 4.4% of the 500 unselected NF1 patients. Genotyping using multiple microsatellite markers may provide a simple, inexpensive, and efficient strategy for screening deletions of the NF1 gene, and can as well be applied for other large genes.

Female↗

PubMed2004

Intronic mutations in the L1CAM gene may cause X-linked hydrocephalus by aberrant splicing.

L1 disease is a clinically heterogeneous X-chromosomal neurodevelopmental disorder that is frequently associated with mental retardation and congenital hydrocephalus in males. It is caused by mutations in L1CAM that encodes a multifunctional transmembrane neuronal cell adhesion molecule. We report our findings on 6 novel intronic L1CAM sequence variants (c.523+5G>A, c.1123+1G>A, c.1547-13delC, c.3323-17dupG, c.3457+3A>T, and c.3457+18C>T), and a recurrent one (c.523+12C>T). While the pathogenic potential of nucleotide changes within the evolutionarily well-conserved splice consensus sequence (c.523+5G>A, c.1123+1G>A, and c.3457+3A>T) is widely accepted, it is not always straight forward to assess the disease relevance of intronic mutations, if they lie outside the consensus. The c.523+12C>T variant co-segregated with X-linked hydrocephalus in two unrelated families. In the mutated allele, a preferentially used novel splice donor site is generated that results in a frame shift due to insertion of the first 10 bp of intron 5 in the mature mRNA, a largely truncated protein, and most likely a functional null allele. The c.1547-13delC mutation creates a new acceptor site resulting in the insertion of 4 additional amino acids at the end of the immunoglobulin like domain 5. In contrast, c.3323-17dupG and c.3457+18C>T seem to be non-pathogenic L1CAM variants.

Base Sequence↗

PubMed2004

Craniofacial hyperostoses in Proteus syndrome -- a case report.

OBJECTIVE: Description of a patient with a rare syndrome leading to the partial overgrowth of craniofacial bones. CASE REPORT: In a 17-year-old female patient with severe hyperostoses of the craniofacial bones asymmetric overgrowth of the right upper and left lower limbs, linear hyperpigmentation of the right arm and a history of regional lipomatosis were found. These manifestations were suggestive of Proteus syndrome. The management of the craniofacial involvement is described and a literature overview presented. CONCLUSION: Proteus syndrome is a rare overgrowth syndrome probably related to a somatic mutation that involves craniofacial structures in about 30% of patients. Early diagnosis is required for adequate interdisciplinary treatment.

Adolescent↗

PubMed2004

Functional consequences of a novel uromodulin mutation in a family with familial juvenile hyperuricaemic nephropathy.

BACKGROUND: Familial juvenile hyperuricaemic nephropathy (FJHN) is an autosomal-dominant disorder featuring hyperuricaemia, low fractional urate excretion, interstitial nephritis and chronic renal failure. The responsible gene UMOD was recently identified. UMOD encodes for uromodulin or Tamm-Horsfall glycoprotein, the most abundant protein in normal urine. We encountered a family with FJHN and identified a novel UMOD mutation in exon 6. METHODS: We sequenced the gene in all family members, identified the mutation, and verified its presence in the affected members. We next performed functional studies of the mutant protein by immunofluorescence and FACS analysis on transfected cells. RESULTS: The mutation p.C347G (c.1039T > G) results in a conserved cysteine to glycine amino acid substitution in the uromodulin zona pellucida (ZP) domain. The cell studies showed that the novel uromodulin mutation causes a delay in protein export to the plasma membrane due to its retention in the endoplasmic reticulum. CONCLUSIONS: We describe the first reported mutation mapping in the ZP uromodulin domain. Our data provide further evidence showing why the excretion of uromodulin is reduced in this syndrome.

Base Sequence↗

PubMed2003

Mutations in bone morphogenetic protein receptor 1B cause brachydactyly type A2.

Brachydactyly (BD) type A2 is an autosomal dominant hand malformation characterized by shortening and lateral deviation of the index fingers and, to a variable degree, shortening and deviation of the first and second toes. We performed linkage analysis in two unrelated German families and mapped a locus for BD type A2 to 4q21-q25. This interval includes the gene bone morphogenetic protein receptor 1B (BMPR1B), a type I transmembrane serinethreonine kinase. In one family, we identified a T599 --> A mutation changing an isoleucine into a lysine residue (I200K) within the glycine/serine (GS) domain of BMPR1B, a region involved in phosphorylation of the receptor. In the other family we identified a C1456 --> T mutation leading to an arginine-to-tryptophan amino acid change (R486W) in a highly conserved region C-terminal of the BMPR1B kinase domain. An in vitro kinase assay showed that the I200K mutation is kinase-deficient, whereas the R486W mutation has normal kinase activity, indicating a different pathogenic mechanism. Functional analyses with a micromass culture system revealed a strong inhibition of chondrogenesis by both mutant receptors. Overexpression of mutant chBmpR1b in vivo in chick embryos by using a retroviral system resulted either in a BD phenotype with shortening and/or missing phalanges similar to the human phenotype or in severe hypoplasia of the entire limb. These findings imply that both mutations identified in human BMPR1B affect cartilage formation in a dominant-negative manner.

Amino Acid Sequence↗

PubMed2003

Antenatal onset of cortical hyperostosis (Caffey disease): case report and review.

We report on a fetus of 27 weeks of gestation whose clinical, radiological, and histopathological findings are compatible with the prenatal form of Caffey disease (cortical hyperostosis). Prenatal ultrasound examination showed polyhydramnios and markedly short and angulated long bones, which had led to the incorrect diagnosis of lethal osteogenesis imperfecta. We found 43 published descriptions on the antenatal onset of cortical hyperostosis symptomatic in utero or at birth. Two groups of prenatal cortical hyperostosis (PCH) can be distinguished: (1) severe (25 reports and the fetus presented here), with onset before 35 weeks of gestation and generally associated with polyhydramnios, lung disease, prematurity, and high lethality; (2) mild (18 reports), with onset after 35 weeks of gestation and without complications. Autosomal recessive inheritance has been suggested for the prenatal form of cortical hyperostosis. However, the available evidence suggests that both dominant and recessive inheritance is possible. Moreover, dominant inheritance seems to be more common in the mild prenatal form of cortical hyperostosis.

Female↗

PubMed2003

Two brothers with findings resembling congenital intrauterine infection-like syndrome (pseudo-TORCH syndrome).

Clinical, pathological, and X-ray findings of two brothers with features resembling congenital intrauterine infection-like syndrome are presented. Extensive screening for intrauterine infection was performed. Nevertheless all confirmatory tests were normal. Both brothers showed extensive intra- and extra-cranial calcifications, thrombocytopenia, a septum pellucidum cyst, one-sided paresis of the diaphragm, and metaphyseal changes on X-ray scans resembling intrauterine infection. Within the first days of life, they developed seizures and died from severe cerebral hemorrhage. The MRI scan of the brain showed cerebellar hypoplasia in one of the boys, while the cerebellum had normal size in the other. No indication of a metabolic disorder, especially in calcium metabolism, was identified. Due to the clinical overlap with Hoyeraal-Hreidarsson syndrome, mutations in the DKC1 gene (Xq28) and the hTR gene (RNA component of telomerase on chromosome 3q) have been excluded. The parents are non-consanguineous and further family history was unremarkable. The findings in these boys overlap with features described in congenital intrauterine infection-like syndrome (pseudo-TORCH syndrome).

Abnormalities, Multiple↗

PubMed2003

Complete physical map and gene content of the human NF1 tumor suppressor region in human and mouse.

Duplicon-mediated microdeletions around the NF1 gene are frequently associated with a severe form of neurofibromatosis type I in a subgroup of patients who show an earlier onset of cutaneous neurofibromas, dysmorphic facial features, and lower IQ values. To clarify the discrepancies between published maps of the NF1 tumor-suppressor gene region as well as the length of gaps in these assemblies and to validate the recently described tandem duplication of the human NF1 locus, we assembled a contiguous high-density map of BAC and PAC clones from different genomic libraries. Although two WI-12393-derived low-copy fragments are known to occur at the proximal and distal boundaries of the 1.5-Mb segment that is usually deleted in NF1 microdeletion patients, we identified an additional WI-12393-related segment between the MGC13061 and the NF1 gene, which appears to trigger interstitial deletions of smaller size as observed in two patients. Moreover, we completed the genomic organization and cDNA structure of all functional genes, CYTOR4, FLJ12735, FLJ22729, CENTA2, MGC13061, NF1, OMG, EVI2B, EVI2A, KIAA1821, MGC11316, HCA66, KIAA0160, and WI-12393, from this region. A comparison of the human map to the orthologous region on mouse chromosome 11 revealed significant differences in the number and arrangement of genes, indicating that many chromosomal breaks with partial duplications, inversions, and deletions occurred predominantly in the primate lineage.

Adult↗

PubMed2003

Spectrum of mutations in PTPN11 and genotype-phenotype correlation in 96 patients with Noonan syndrome and five patients with cardio-facio-cutaneous syndrome.

Noonan syndrome (NS) is a relatively common, but genetically heterogeneous autosomal dominant malformation syndrome. Characteristic features are proportionate short stature, dysmorphic face, and congenital heart defects. Only recently, a gene involved in NS could be identified. It encodes the non-receptor protein tyrosine phosphatase SHP-2, which is an important molecule in several intracellular signal transduction pathways that control diverse developmental processes, most importantly cardiac semilunar valvulogenesis. We have screened this gene for mutations in 96 familial and sporadic, well-characterised NS patients and identified 15 different missense mutations in a total of 32 patients (33%), including 23 index patients. Most changes clustered in one exon which encodes parts of the N-SH2 domain. Five of the mutations were recurrent. Interestingly, no mutations in the PTPN11 gene were detected in five additional patients with cardio-facio-cutaneous (CFC) syndrome, which shows clinical similarities to NS.

DNA Mutational Analysis↗

PubMed2003

Mutations in NSD1 are responsible for Sotos syndrome, but are not a frequent finding in other overgrowth phenotypes.

Recently, deletions encompassing the nuclear receptor binding SET-Domain 1 (NSD1) gene have been described as the major cause of Japanese patients with the Sotos syndrome, whereas point mutations have been identified in the majority of European Sotos syndrome patients. In order to investigate a possible phenotype-genotype correlation and to further define the predictive value of NSD1 mutations, we performed mutational analysis of the NSD1 gene in 20 patients and one familial case with Sotos syndrome, five patients with Weaver syndrome, six patients with unclassified overgrowth/mental retardation, and six patients with macrocephaly/mental retardation. We were able to identify mutations within the NSD1 gene in 18 patients and the familial case with Sotos syndrome (90%). The mutations (six nonsense, eight frame shifts, three splice site, one missense, one in-frame deletion) are expected to result in an impairment of NSD1 function. The best correlation between clinical assessment and molecular results was obtained for the Sotos facial gestalt in conjunction with overgrowth, macrocephaly, and developmental delay. In contrast to the high mutation detection rate in Sotos syndrome, none of the patients with Weaver syndrome, unclassified overgrowth/mental retardation and macrocephaly/mental retardation, harbored NSD1 mutations. We tested for large deletions by FISH analysis but were not able to identify any deletion cases. The results indicate that the great majority of patients with Sotos syndrome are caused by mutations in NSD1. Deletions covering the NSD1 locus were not found in the patients analyzed here.

Adult↗

PubMed2002

Segmental neurofibromatosis.

Segmental neurofibromatosis is characterised by a limited, segmental distribution of cutaneous neurofibromatosis type 1 (NF1) lesions. It has been suggested that segmental NF results from a postzygotic NF1 gene mutation, and, recently, this hypothesis has been proven in a patient with regionally distributed café-au-lait (CAL) spots and freckles by demonstrating an NF1 microdeletion restricted to fibroblasts cultured from CAL spots. We describe here a patient with segmental NF in which we could not demonstrate any NF1 gene mutation in fibroblasts cultured from neurofibromas by use of the protein truncation test, enzymatic mutation detection and fluorescence in situ hybridisation. These data are in line with the concept that NF1 mutations in Schwann cells, but not in fibroblasts, correlate with neurofibroma formation.

Humans↗