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Analysis of the patterns of inheritance of splenomegaly and serum IgM levels in the Watut of Papua New Guinea.

Hyperreactive malarious splenomegaly (HMS) reflects abnormal immune responses to malarial infection. The central question is whether HMS results from unusual patterns of malarial infection or from immune incompetence in the host. Family distributions of two features of the syndrome, splenomegaly and excessively high IgM levels, have been examined in a Papau New Guinea population in which HMS is exceptionally common. Segregation analysis of spleen grade shows that a major sex-linked gene controls hyperresponsiveness to malaria. This finding is supported by additional segregation analysis, which shows that an autosomal locus cannot account for a significant proportion of variation in spleen grade, and by path analysis, which rejects a model that assumes that parents contribute equally to the child's genotype. The sex-linked gene contributing to HMS was not mediated through sex linkage of a major gene for IgM concentrations, as shown by segregation analysis. It has yet to be determined whether this pattern of inheritance also applies to HMS occurring sporadically in other less severely affected populations. The applicability of these findings to the general variability in "normal" IgM responses to malaria also remains to be established.

Adult

The inheritance of vertebral shape in the mouse. I. A study using Fourier analysis to examine patterns of inheritance in the morphology of cervical and upper thoracic vertebrae.

The shapes of cervical and upper thoracic vertebrae from large samples of 2 inbred strains of mice and their F1 offspring were examined using Fourier analysis to investigate in detail the distributions and magnitudes of differences in vertebral shape between different strains of mice, the relationships between parents and offspring and any differences in the inheritance of vertebral shape between successive vertebral levels. Consistent with the findings of an earlier study there was evidence for considerable differences between vertebral levels in the degree to which offspring resemble one or other parent. The results demonstrate that the inheritance of vertebral morphology conforms to a model in which F1s between inbred strains form a triangular relationship with their parents. Furthermore, this relationship varies between vertebral levels. The significance of these findings is considered in relation to the understanding of the mechanisms of character inheritance and evolution and some new directions for research into vertebral column morphogenesis are proposed.

Animals

Applied genetics for the practicing optometrist.

A good preventive blindness program includes a strong program in genetic counseling. Optometrists can be of substantial assistance to a genetic counseling program by: 1) being informed of the various types of inherited ocular disorders, and their modes of transmission. 2) becoming aware of the presence of disorders in other members of the patient's family, and 3) encouraging the affected family members to seek genetic counseling prior to conception. This article is designed to serve as a guide for familiarizing the practicing O.D. with the various types of inheritance patterns, specific disorders which follow these inheritance patterns, and some of the ocular and systemic characteristics of the disorders. Only those anomalies of structure and/or function which have an identifiable (and therefore a predictable) genetic mode of transmission will be discussed. This article is intended to serve as a brief and general review of some of the more common ocular disorders, and not as a comprehensive text on the genetics of ophthalmic diseases. Emphasis is placed on the optometric management of each disease discussed.

Child

The role of dominance and epistasis in the genetic control of blood pressure in rodent models of hypertension.

Genetic analyses of crosses between hypertensive rodent models and their normotensive controls were performed on 43 sets of data published between 1970-1989. In each case, the cross involved F1, F2, and both backcross generations for a "complete genetic cross." Biometrical analysis estimated genetic parameters and their standard errors associated with dominance and epistasis (interaction of alleles that are not at the same locus). The statistical significance of these parameters was determined by comparing the parameter to its standard error. A purely additive inheritance pattern was seldom found. Additive/dominance inheritance was apparent in only two models. The prevailing pattern of inheritance was one with partial dominance for alleles for normal blood pressures and epistatic interactions. Finding epistasis in so many models will have implications for the application of cosegregation and linkage analyses in hypertension research.

Animals

Investigation of the prevalence and inheritance of bronchial asthma in San Antonio de los Baños, Cuba.

A survey of bronchial asthma prevalence and inheritance patterns was carried out in the municipality of San Antonio de los Banõs, La Habana, Cuba, employing as a sample 3,295 of the area's inhabitants. These persons, selected by stratified, non-restricted sampling techniques, represented 11.02 per cent of the total population. The asthma prevalence found in this sample, which was considered representative of the local population, was 9.74 percent. No significant variations were noted in male and female prevalence rates. The occurrence of bronchial asthma is strongly influenced by inheritance. Our survey supported this view, and also showed that the age of asthma onset is influenced by whether or not the subject's family has a positive history of allergy or not. However, patients with a positive history on one side of their family had an age of onset that was not significantly different from patients with a positive history on both sides (p less than 0.35). Overall, the results tend to confirm that the inheritance of bronchial asthma is autosomal and does not conform to simple dominant or recessive inheritance patterns. Rather, asthma inheritance appears multifactorial, perhaps involving varying degrees of expression, indicating that more is involved than absence or deficiency of a single enzyme.

Adolescent

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

Thyroxine binding globulin deficiency in a family with type I hyperlipoproteinaemia.

A familial type I hyperlipoproteinaemia is described in three members of a family of eleven; on the basis of LPL activity and HDL content of plasma three other members of the family have been diagnosed to be heterozygotes without other disturbances in their lipid spectrum. The distribution of this lipid disorder is in accordance with an autosomal recessive inheritance pattern. In this family a second hereditary condition, thyroxine binding globulin deficiency, was found in addition to the hyperlipoproteinaemia. The inheritance of this condition appears to be as an autosomal dominant. An interrelated inheritance pattern of both conditions could not be proved, but both traits may be located on the same chromosome at some distance from another to allow recombination.

Adult

Bilateral absence of the kidneys and ureters. Three cases reported in one family.

Three infant boys with bilateral absence of the kidneys and hypoplasia of the lungs are described. Two of the infants were brothers and the third was a first cousin. They were born to 2 sisters whose husbancs were unrelated to their wives and to each other. None of the parents had renal problems. The occurrence of this syndrome in 2 male sibs is suggestive of an autosomal recessive inheritance pattern which has been previously described. An additional male first cousin born to the mother's sister is sugesstive of sex-linked inheritance for this particular family, an inheritance pattern not previously described.

Abnormalities, Multiple

Prognostic significance of nondiploid DNA determined by flow cytometry in sporadic and familial medullary thyroid carcinoma.

To clarify the role of DNA measurements in predicting outcome after surgical treatment of medullary thyroid carcinoma (MTC), we performed flow cytometric analysis in nuclear suspensions of 119 MTC tumors. Of the 119 patients, 63 (53%) patients had sporadic tumors and 56 (47%) patients had familial tumors; survivors were followed for a mean of 13 years. DNA content was normal in 92 (77%) patients and abnormal (nondiploid) in 27 (23%) patients. Ten-year cause-specific mortality rates were 12%, 42%, and 49% with diploid, tetraploid/polyploid, or aneuploid tumors (p = 0.0009) and were greater with nondiploid tumors both in the sporadic (p = 0.012) and multiple endocrine neoplasia (familial) cases (p = 0.114). None of 27 patients with TNM stage I disease died of MTC. In patients with TNM stages II, III, and IV disease, DNA nondiploid tumors were associated with increased deaths from MTC. In a Cox proportional hazards model involving all 119 patients and adjusted for disease stage and inheritance pattern, nondiploid DNA was independently associated with increased deaths from MTC (p = 0.008). In an identical Cox model restricted to the 92 DNA diploid tumors, an S-phase fraction of 15.0% or more remained a significant variable (p = 0.034) after adjustment for stage and inheritance pattern. We therefore conclude that DNA measurements do have a role to play in predicting outcome after surgical treatment of MTC.

Adolescent

An RFLP map of the Plasmodium falciparum genome, recombination rates and favored linkage groups in a genetic cross.

We report a genetic linkage map of the Plasmodium falciparum genome, using the inheritance patterns of nearly 90 RFLP markers in a genetic cross. Markers were assigned to polymorphic loci on all 14 nuclear chromosomes. Genetic recombination between parental markers was detected in each of the progeny, indicating that progeny from cross-fertilization events were favored over progeny from self-fertilization of either parent alone. Inheritance patterns among the markers suggested that certain parental linkage groups on chromosomes 2, 3, 12 and 13 were favored in the cross. Recombination frequencies on five chromosomes indicated an approximate map unit size of 15-30 kb per centiMorgan for P. falciparum.

Animals

Linkage analysis of schizophrenia: challenges and promise.

Schizophrenia is a serious mental illness affecting nearly 1 per cent of the general population. Family, twin, and adoption studies suggest that genetics plays a major role in the etiology of schizophrenia. The inheritance pattern appears complex, similar to that of other common conditions like heart disease. To uncover a causal genetic factor, researchers have recently begun to apply a linkage analysis strategy to schizophrenia. Early results suggest that there are many challenges facing scientists who undertake schizophrenia genetics research. While one study has shown significant linkage of schizophrenia to a region on chromosome 5, several other studies have not found linkage to this area. The likelihood that there are several major genes predisposing to the illness and uncertainties about inheritance patterns and diagnostic boundaries are potential difficulties to overcome. Many more families need to be studied, and creative complementary research strategies pursued, to achieve the potential success offered by a genetic linkage approach.

Adolescent

Genetic Analysis of Genomic and Methylomic Variation and Identification of Multi-Trait Mutants in Rice Carried on Chang'e-5.

Global food security is facing challenges from population growth to diminishing arable land. Space mutation breeding holds promise for overcoming the variation limitations in conventional breeding; however, the mutagenic effects of the deep-space environment on rice and the transgenerational inheritance patterns of induced variations remain unclear. In this study, rice seeds carried by the Chang'e-5 spacecraft were used as materials. Whole-genome sequencing and whole-genome bisulfite sequencing were performed on the first (SP1) and second generations (SP2) of space-mutagenized plants after their return to Earth. The results showed that the number of genomic variants in the SP2 generation increased significantly compared with SP1, and SNPs, homozygous sites, and variants in coding regions were more heritable. The genome-wide methylation level was elevated in the SP2 generation, and among differentially methylated cytosines, those in the CG context exhibited the highest heritability. Furthermore, large-scale screening for nitrogen efficiency, tolerance to PEG-induced stress, and germination-stage cold resistant mutants was conducted in the SP2 generation, and phenotypic validation was performed in the third generation (SP3). By integrating multi-omics analyses of representative mutants to mine candidate genes, a number of heritable elite mutants were obtained, and seven candidate genes for key traits were identified. This study systematically elucidates the transgenerational inheritance patterns of deep-space-induced variation in rice. The multi-trait mutants obtained provide valuable germplasm resources for gene cloning and breeding applications in rice.

DNA methylation

Familial variable immunodeficiency: autosomal dominant pattern of inheritance with variable expression of the defect(s).

In 1963, Rosen and Bougas reported the case of a woman with recurrent infection, marked elevation of 19S, and virtual absence of 7S gamma globulin. Recently, members of her family were found to have similar abnormalities: Ten of the 37 family members tested had elevated levels of serum IgM accompanied by a combined deficiency of IgG and IgA in three, and by a deficiency of either IgG or IgA in two. In five, an increase in IgM was the sole abnormality. Two children had deficiencies of IgG and IgA with normal serum levels of IgM. Ten of the 12 affected individuals had no IgD detectable by radial immunodiffusion and six had a low percentage of IgG-bearing B lymphocytes. A lack of correlation between the immunochemical abnormalities and either the presence or severity of clinical illness was observed. The presence of immunodeficiency in three generations and in both sexes of this family suggests an autosomal dominant mode of inheritance with variable penetrance of the defect.

Adolescent

Bilateral Wilms' tumour. Age at diagnosis, associated congenital anormalies, and possible pattern of inheritance.

A series of 87 patients with Wilms' tumour seen during the period 1960-73 included 11 (13%) with bilateral tumours. 6 patients presented with simultaneous bilateral tumours, 2 had tumours in each side of a horseshoe kidney, and 3 later developed a tumour in the remaining kidney. There was no reported familial incidence of Wilms' tumour. Maternal age at birth of the patients with simultaneous bilateral tumours was over 30 years in 7/8 cases. The average of patients with bilateral tumours was 15 months, whereas that of patients with unilateral tumours was 31/2 years. All the simultaneously occurring bilateral tumours and those within a horseshoe kidney were multifocal, whilst the sequentially occurring bilateral tumours and the unilateral tumours all developed as a single tumour mass within the affected kidney. Associated congenital anomalies were found in 5 (45%) of 11 patients with bilateral tumours, several of whom had more than one defect. Of 76 patients with a unilateral tumour, only 3 (4%) had congenital anomalies.

Age Factors

Genetic analysis of natural populations of Poeciliopsis monacha: Allozyme inheritance and pattern of mating.

The genetic bases of seven polymorphic enzymes in Poeciliopsis monacha have been demonstrated through the analysis of allelic segregation in presumed heterozygotes captured in natural populations. Tests of linkage among loci revealed a significant association between two loci, Ldh-1 and Idh-2. Evidence for multiple insemination was detected in 23 percent of the females examined. Considering the limited number of markers available in the present study, it is probably that the actual frequency of multiple insemination is much higher.

Alleles