Familial Pattern Of Inheritance Research Articles

Testing association in the presence of linkage — a powerful score for binary traits

We present a score for testing association in the presence of linkage for binary traits. The score is robust to varying degrees of linkage, and it is valid under any ascertainment scheme based on trait values as well as under population stratification. The score test is derived from a mixed effects model where population level association is modeled using a fixed effect and where correlation among related individuals is allowed for by using log-gamma random effects. The score, as presented in this paper, does not assume full information about the inheritance pattern in families or parental genotypes. We compare the score to the semi-parametric family-based association test (FBAT), which has won ground because of its flexible and simple form. We show that a random effects formulation of co-inheritance can improve the power substantially. We apply the method to data from the Collaborative Study on the Genetics of Alcoholism. We compare our findings to previously published results.

Familial membranous subaortic stenosis: Review of familial inheritance patterns and a case report

Discrete subaortic stenosis (DSS) accounts for 8% to 20% of all cases of left ventricular outflow tract (LVOT) obstruction. 1 Familial incidence of DSS, although very rare, signifies the importance of screening in family members. Thus far, a clear inheritance pattern has not been reported in any single pedigree. We have described a family with 2 affected children (out of 3) and have also reviewed the inheritance patterns observed in the reported familial cases of DSS. Most cases of DSS present with systolic murmurs and with time progress to systolic dysfunction. Therefore we also explored the relationship between age and the peak LVOT pressure gradient in the familial cases. Clinical Summary PATIENT 1. A 3-month-old infant presented with recurrent pulmonary infections, congestive heart failure, and failure to thrive. On examination, he had a machinery murmur. Echocardiography revealed a large patent ductus arteriosus, mild pericardial effusion, severe left ventricular hypertrophy (LVH), moderate-to-severe subaortic stenosis, a normal aortic valve, and the presence of a subaortic membrane (Figure E1, A). The peak pressure gradient was 70 mm Hg, and the mean pressure gradient was 45 mm Hg. The child underwent surgical intervention for closure of the patent ductus arteriosus during the same admission and an elective operation for subaortic membrane removal at the age of 21 months. The subaortic membrane, surrounding hypertrophied muscles, and free wall were excised. Histopathology showed fibromuscular tissue fragments exhibiting secondary regenerative changes on a myxoid background. A follow-up echocardiogram showed moderate LVH, a peak pressure gradient of 51 mm Hg, and a mean pressure gradient of 32 mm Hg. PATIENT 2. A 5-year-old, otherwise healthy sister of the proband was found to have a heart murmur. Echocardiography showed the presence of a subaortic membrane (Figure E1, B), moderate aortic stenosis, and moderate LVH. The LVOT pressure gradient was 90 mm Hg, and the mean pressure gradient was 55 mm Hg. She underwent elective surgical excision of the subaortic membrane, hypertrophied muscles, and free wall. Histopathology revealed fibromuscular tissue showing spindle-shaped cells with abundant intercellular connective tissue stroma. Postoperative echocardiography showed moderate aortic valvular stenosis and a peak pressure gradient of 72 mm Hg.

A85. Electrophysiological characteristics and connexin 43 in transgenic mice overexpressing the human PRKAG2 gene

Mutations in the non-catalytic, γ-2 regulatory subunit of the PRKAG2 gene are associated with Wolff-Parkinson-White (WPW) syndrome and cardiac hypertrophy with a familial autosomal dominant pattern of inheritance. Patients and transgenic mutant mice overexpressing mutant PRKAG2 gene have excessive glycogen storage, electrophysiological abnormalities and cardiac hypertrophy. Whether these alterations have a consistent anatomical pattern of expression is unknown. Cardiac myocyte conduction utilizes gap junctions, which may be reduced in pathological hypertrophy.

Skin wound healing in the first generation (F1) offspring of Yorkshire and red Duroc pigs: Evidence for genetic inheritance of wound phenotype

Fibroproliferative scars in humans often demonstrate familial inheritance patterns, and genetics may contribute to healing and scarring. Genetic factors may also influence the scarring phenotype in a porcine model. Healing of full thickness excisional skin wounds in Yorkshire pigs closely resembles normal healing in humans, while identical wounds in red Duroc pigs form hypercontracted, hyperpigmented scars. The present study has evaluated the healing process in the first generation cross (F1) of red Duroc and Yorkshire pigs. Gross and histologic analysis revealed that the F1 animals exhibit an intermediate healing phenotype, with some features of each parent breed. F1 full thickness wounds were significantly hypercontracted and fibrotic, but apigmented. Analysis of mRNA expression patterns for a panel of relevant molecules ( N = 32) in the F1 animals revealed some similarities to each parent breed, as well as unique patterns for other molecules. Furthermore, a depth dependency to the healing response was observed at the gross, histologic, and molecular levels, with deep dermal wounds healing similar to Yorkshire wounds. These findings suggest that the genetic contribution to scar phenotype in this animal model is complex. However, the results indicate that further understanding in this model may provide insights into risk factors for hypertrophic scarring in human burn patients.

Patterns of Inheritance of Essential Hypertension in Hundred Iranian Families

Background: Essential hypertension tends to a familial mode. Its pattern of inheritance is heterogeneous, but the frequencies of different mode of inheritance vary in different populations. Determining of the mode of inheritance in each family is the basic information that is needed for the risk estimation in those family members. Determination of pattern of inheritance in families with at least two members affected with essential hypertension in Hamadan city, west of Iran, was the goal of the present paper. Methods: The present study was a cross sectional descriptive one. The cases were patients in Dr Emami Clinic in Hamadan that were diagnosed as essential hypertension and also a familial recurrence pattern among their families. Then we prepared a suitable questionnaire containing some questions about their medical and family histories as well as pedigree containing 3 to 4 generations. After drawing their pedigree we determined their patterns of inheritance based on the standard method. The data were expressed in tables according to our variables to show the results. Totally we could include 100 families in this study. Results: The number of live patients in 100 studied families was 285 (84 males and 201 females, average= 62.7 y). Our primary results showed that the ages of diagnoses were from 30 to 81 y (average 54.24) for men and 28, 90 and 54.127 y in that order for women. The consanguineous marriages were done in 10.52% of the parents of affected persons (8.07% degree 3 and 2.45% degree 4). Frequencies of patients in different age groups, according to the age of diagnosis, were statistically significant ( P Conclusion: Essential hypertension in our subject families was heterogenic. Their frequency orders were multifactorial, autosomal dominant and autosomal recessive trait, respectively. Such order is adopted with the literature but it seems that in our population, the essential hypertension with autosomal recessive mode is more frequent than the western populations.

Obesity in Infancy: Questions, More Questions, and Few Answers

Current literature presents conflicting views about the existence of infant obesity and its role as a risk factor for later life obesity and comorbidity. This article reviews extant literature and addresses the issues raised about obesity and overweight status in the first 2 years of life. The epidemic increase in childhood obesity stimulates questions about the effects of body weight changes during infancy upon future health status. The influence of maternal obesity and family inheritance patterns is a significant risk for childhood obesity, yet the picture is unclear for birthweight, infant weight gain, and growth parameters in the earliest years of life. Prevention, management, and treatment are indicated when families present with obesity patterns among their members.

Support for Polygenic Influences on Ocular Refractive Error

Refractive errors, myopia, and hyperopia are common conditions requiring corrective lenses. The familial clustering of myopia has been well established. Several chromosomal regions have been linked to high myopia (12q, 17q, and 18q), to quantitative refraction among twins (3q, 4q, 8p, and 11p), and to families with moderate myopia (22q). This study examined the familial aggregation and pattern of inheritance of ocular refraction in an adult population, by using data from the Beaver Dam Eye Study. Familial correlations were examined and segregation analysis was performed on the average refractive error measurements in the right and left eyes after adjustment for age, sex, and education. Analyses were based on 2138 individuals in 620 extended pedigrees with complete data on age, sex, education, and spherical equivalent. Substantial positive correlation was found between siblings (0.33), parents and offspring (0.17), and cousins (0.10) and lower correlation among avuncular pairs (0.08) after adjustment for age, sex, and years of education. The results of this segregation analysis do not support the involvement of a single major locus throughout the entire range of refractive error. However, models allowing for familial correlation, attributable in part to polygenic effects, provided a better fit to the observed data than models without a polygenic component, suggesting that several genes of modest effect may influence refractive error, possibly in conjunction with environmental factors. These results support the involvement of genetic factors in the etiology of refractive error and are consistent with reports of linkage to multiple regions of the genome.

A locus for generalized tonic-clonic seizure susceptibility maps to chromosome 10q25-q26

Inheritance patterns in twins and multiplex families led us to hypothesize that two loci were segregating in subjects with juvenile myoclonic epilepsy (JME), one predisposing to generalized tonic-clonic seizures (GTCS) and a second to myoclonic seizures. We tested this hypothesis by performing genome-wide scan of a large family (Family 01) and used the results to guide analyses of additional families. A locus was identified in Family 01 that was linked to GTCS (10q25-q26). Model-based multipoint analysis of the 10q25-q26 locus showed a logarithm of odds (LOD) score of 2.85; similar results were obtained with model-free analyses (maximum nonparametric linkage [NPL] of 2.71; p = 0.0019). Analyses of the 10q25-q26 locus in 10 additional families assuming heterogeneity revealed evidence for linkage in four families; model-based and model-free analyses showed a heterogeneity LOD (HLOD) of 2.01 (alpha = 0.41) and maximum NPL of 2.56 (p = 0.0027), respectively, when all subjects with GTCS were designated to be affected. Combined analyses of all 11 families showed an HLOD of 4.04 (alpha = 0.51) and maximum NPL score of 4.20 (p = 0.000065). Fine mapping of the locus defined an interval of 4.45Mb. These findings identify a novel locus for GTCS on 10q25-q26 and support the idea that distinct loci underlie distinct seizure types within an epilepsy syndrome such as JME.

Proposed multigenic Composite Inheritance in major depression

Various rationale have been considered in the familial inheritance pattern of major depression ranging from simple one-gene Mendelian inheritance to pseudo-additive gene action. We instead predict broad genetic expressivity patterns in the progeny of parents where at least one parent has recurrent major depression. In keeping with this idea, we feel that recurrent major depression could involve an expression imbalance of "normal" genes either exclusively or along with allelic variation(s). The patterns of pathology are theoretically conceptualized as qualitative and quantitative, meaning that expressivity of the genetic pattern in these children may range from minimal to complete even among siblings. Thus, prediction of the particular genetic pattern expressed by a particular child might prove difficult. The complex inheritance pattern that we propose is referred to as Composite Inheritance. Composite Inheritance considers that both the up- and down-regulation of luxury genes and housekeeping genes are involved in this dichotomous qualitative inheritance pattern and also the wide quantitative expressivity. The luxury genes include such genes as those coding for the neurotransmitter transporters and receptors. The housekeeping genes found to date include those that code for proteins involved in gene transcription, secondary signaling systems, fatty acid metabolism and transport, and intracellular calcium homeostasis. Other luxury and housekeeping genes no doubt remain to be discovered. Our current research utilizes an empirical approach involving advanced genomics and specialized pattern recognition mathematics in families having at least one parent with recurrent major depression. The goal of our research is to develop a pattern recognition system of genetic expressivity in major depression to which prevention and early intervention may be tailored.

One hundred fifty-four genetic markers for the turkey (Meleagris gallopavo)

Identifying and selectively breeding for improved traits is one of the ultimate goals of genetic research in agriculturally important species. Genome characterization and analysis are important first steps in this process. Genetic linkage maps based on the linear order of polymorphic DNA markers are typically developed through statistical analysis of inheritance patterns in pedigreed families. To develop microsatellite markers for further improvement of the turkey genetic linkage map, small-insert genomic libraries were screened for tandem repeats. Oligonuclotide primers were designed to amplify 164 microsatellite-containing fragments from genomic DNA. Genetic polymorphisms at 154 markers were determined by genotyping the F(1) individuals of two resource populations. Markers determined as segregating in the University of Minnesota/Nicholas Turkey Breeding Farms (UMN/NTBF) reference population were used to genotype F(2) individuals and a two-point linkage analysis was performed.

Anticipation and phenotype in familial intracranial aneurysms

Background: In familial intracranial aneurysms there is evidence for genetic heterogeneity, probably from mutations at separate loci. Objectives: To compare demographic and clinical features in patients of families with familial...

Epidemiology, clinical presentation and diagnosis of onychomycosis.

Onychomycosis is a common nail disease, responsible for up to 50% of diseases of the nail. The distribution of different pathogens is not uniform; it depends on various factors such as climate, geography and migration. However, studies have revealed that two dermatophytes, Trichophyton rubrum and Trichophyton mentagrophytes, account for more than 90% of onychomycoses. Onychomycosis can be divided into four major clinical presentations: distal subungal (the most common form of the disease), proximal subungal (the most common form found in patients with human immunodeficiency virus infection), and superficial and total dystrophic onychomycosis. Onychomycosis is a multifactorial disease. Age has a very important effect on the occurrence of onychomycosis, with a correlation between increasing age and infection. Genetics has also been identified as a factor governing the epidemiology of onychomycosis; T. rubrum infection shows a familial pattern of autosomal dominant inheritance. Disease and lifestyle may also play a role in the epidemiology of fungal nail infections. Studies have shown that diabetes, acquired immunodeficiency syndrome and peripheral arterial disease may be independent predictors of onychomycosis. Because of the multifactorial nature of the epidemiology, accurate diagnosis, pertinent treatment and patient education must be paramount when treating the disease.

X chromosome inactivation patterns in Russell-Silver syndrome patients and their mothers.

Russell-Silver syndrome (RSS) is a disorder characterized by pre- and post-natal growth deficiency, triangular facies, relative macrocephaly, and body asymmetry. Maternal uniparental disomy for chromosome 7 has been found in approximately 10% of RSS cases, while the cause in the remaining cases is unknown. Although most cases of RSS are sporadic, at least 25 families have been reported with familial RSS and inheritance patterns of RSS consistent with an X-linked dominant mutation. Thus, we hypothesized that skewed X-chromosome inactivation (XCI) could be increased in some females with RSS as a consequence of a tendency to have the mutant allele on the predominantly active chromosome. Alternatively, unaffected mothers of children with RSS may tend to be skewed due to preferential inactivation of the mutant allele. In support of this last hypothesis, a significant increase in extremely skewed XCI (>95%) was found in mothers of children with RSS (4 of 21, 19%) compared to controls (2 of 101, 2%) (P = 0.008). However, an increase in skewed XCI was also observed in female patients who had unexplained short stature but did not fulfill the criteria for RSS (3 of 17, 18%) (P = 0.02), but not in those diagnosed as RSS (0 of 7, n.s.). Different mechanisms may underlie the increase in skewing in each group, possibly being due to different X-linked mutations or growth restriction during very early in utero development.

The epsilon-sarcoglycan gene (SGCE), mutated in myoclonus-dystonia syndrome, is maternally imprinted.

Myoclonus-dystonia syndrome (MDS) is a non-degenerative neurological disorder that has been described to be inherited in an autosomal dominant mode with incomplete penetrance. MDS is caused by loss of function mutations in the epsilon-sarcoglycan gene. Reinvestigation of MDS pedigrees provided evidence for a maternal imprinting mechanism. As differential methylated regions (DMRs) are a characteristic feature of imprinted genes, we studied the methylation pattern of CpG dinucleotides within the CpG island containing the promoter region and the first exon of the SGCE gene by bisulphite genomic sequencing. Our findings revealed that in peripheral blood leukocytes the maternal allele is methylated, while the paternal allele is unmethylated. We also showed that most likely the maternal allele is completely methylated in brain tissue. Furthermore, CpG dinucleotides in maternal and paternal uniparental disomy 7 (UPD7) lymphoblastoid cell lines show a corresponding parent-of-origin specific methylation pattern. The effect of differential methylation on the expression of the SGCE gene was tested in UPD7 cell lines with only a weak RT-PCR signal observed in matUPD7 and a strong signal in patUPD7. These results provide strong evidence for a maternal imprinting of the SGCE gene. The inheritance pattern in MDS families is in agreement with such an imprinting mechanism with the exception of a few cases. We investigated one affected female that inherited the mutated allele from her mother. Surprisingly, we found the paternal wild type allele expressed whereas the mutated maternal allele was not detectable in peripheral blood cDNA.

Mutational analysis of Hungarian patients with androgen insensitivity syndrome.

To support the clinical diagnosis of androgen insensitivity syndrome (AIS), we performed mutational analysis of the androgen receptor gene. Clinical, hormonal and molecular genetic data of ten undervirilized genetic male patients living in Hungary were recorded. PCR-based single strand conformation polymorphism (SSCP) analysis was used to study the whole coding region of the androgen receptor gene. Direct fluorescent sequencing was applied when aberrant migration was detected by SSCP. Five different mutations were identified in five unrelated genetic male patients with abnormal sexual differentiation. One of these mutations was novel, while the other four mutations have been described previously in the literature. One of the mutations identified earlier in individuals with sporadic AIS showed a familial inheritance pattern in our study group. No abnormality of the androgen receptor gene was identified in three patients clinically suspected to have partial AIS. Application of molecular techniques helped to clarify the diagnosis in patients with disorders of male sexual differentiation.

Pedigree analysis of constitutional delay of growth and maturation: determination of familial aggregation and inheritance patterns.

To investigate the genetic basis of constitutional delay of growth and maturation (CD), 41 families of CD probands underwent interviews regarding pubertal timing, and 12 additional families had history data analyzed from medical records. The family histories of the 53 probands (40 boys and 13 girls) were assessed for pubertal delay using both strict criteria (pubertal delay >or=2 SD beyond the mean) and relaxed criteria (pubertal delay >or=1 SD beyond the mean). These pedigrees were compared with 25 control pedigrees. Mean age of menarche was 14.3 +/- 1.4 yr for mothers of CD probands vs. 12.7 +/- 1.4 yr for mothers of controls (P < 0.0001). Thirty-eight percent of CD mothers met the strict 2 SD criteria, and an additional 29% met the relaxed 1 SD criteria for pubertal delay. By contrast, among the control mothers, 12% met the strict and an additional 8% met the relaxed criteria (P < 0.0001 for comparison with CD mothers). CD fathers were also more likely than the control fathers to have a history of pubertal delay. For first-degree relatives, the estimated relative risk of meeting the 2 SD and 1 SD criteria for delay in CD vs. control pedigrees were 4.8 and 4.9, respectively; estimated relative risk for second-degree relatives were 3.2 and 4.4, respectively. Inheritance patterns varied, but many families showed an apparent autosomal dominant pattern, with or without incomplete penetrance. Although many genes may underlie CD, the inheritance patterns suggest that there are also single genes with major effects whose penetrance is likely affected by genetic or environmental modifiers. The future identification of these major and modifying genes is an exciting prospect that would improve our understanding of the factors that regulate human pubertal timing and modulate the human reproductive endocrine axis.

The poisoning women of Tiszazug.

This article examines the social causes of the infamous Tiszazug murders (i.e., the poisoning of more than forty people, mainly men, by their female relatives) in interwar Hungary. First, it looks at those elements in peasant culture, such as the traditional neglect of the sick elderly and the disabled, which proved conducive to a violent solution of family problems. Then, the essay analyzes the changes in family structures and inheritance patterns and discusses the impact of political events such as the end of overseas migration, the dissolution of the Austro-Hungarian Empire, the autarchic policies of the "successor states" and the failure of land reform on peasants' lives. Finally, the article looks at the discovery of the murders and the peasants' interpretations of the poisonings.

Clinical characteristics of patients with unicoronal synostosis and mutations of fibroblast growth factor receptor 3: a preliminary report.

Clinical teaching dictates that isolated unicoronal synostosis is sporadic in occurrence and is possibly related to intrauterine constraint. Despite this, isolated reports document a familial occurrence. It has previously been recognized that there may be a familial pattern of inheritance. Recently, mutations in fibroblast growth factor receptors (FGFRs) have been implicated in several syndromic craniosynostoses. At the authors' institution, mutations in FGFR3, located at chromosome 4p16, have been found to cause coronal synostosis. Two cases of unicoronal synostosis were found to have the same Pro250Arg missense mutation in FGFR3. This finding suggested that all patients with a diagnosis of unicoronal synostosis be screened for the FGFR3 mutation. Between January and December of 1996, patients with a diagnosis of plagiocephaly at the Children's Hospital of Philadelphia were evaluated for the FGFR3 mutation. Thirty-seven patients with unicoronal synostosis had mutational studies. Two additional patients were known to have the FGFR3 mutation at the onset of the study. Of the 37 patients screened, four were found to have the FGFR3 mutation, for a total of six patients with both unicoronal synostosis and the FGFR3 mutation. All patients with unicoronal synostosis were evaluated for facial dysmorphology and operative outcome. The six patients with the FGFR3 mutation had more severe cranial dysmorphology and were more likely to need surgical revision than those without the FGFR3 mutation. The occurrence of the FGFR3 mutation among patients with unicoronal synostosis provides evidence for a genetic basis of certain forms of plagiocephaly. The clinical, radiologic, and molecular findings will be an important addition to the surgical management and counseling of patients with unicoronal synostosis.

Detection of errors in dinucleotide repeat typing by nondenaturing electrophoresis.

This study shows that consideration of minor bands (heteroduplex, shadow, and faint bands) associated with allele bands in nondenaturing polyacrylamide gel electrophoresis (PAGE) after polymerase chain reaction (PCR) is effective for detecting PCR processing errors that lead to mistyping of heterozygotes as homozygotes. Notably, we show that minor bands in native gels are highly effective for detecting allele dropout and preferential amplification in PCR amplification of dinucleotide repeats. These findings are based on an analysis of Mendelian inheritance patterns in families, and the reproduction of heterozygous band patterns by mixing homozygous DNAs before PCR, for a total of six (AC)n repeats located on human chromosome 11p15. To investigate the utility of our approach, a large population sample of 405 unrelated individuals was genotyped for each (AC)n repeat using minor bands as internal quality controls. Genotype frequencies at each of the six loci were in close agreement with Hardy-Weinberg proportions, which suggests that there were few genotyping errors. Our observations add to the evidence indicating that minor bands in native gels are of diagnostic value in the genotyping of dinucleotide repeats.

Familial Correlation of Immunoglobulin G Subclass Responses to Plasmodium falciparum Antigens in Burkina Faso

Host genes are thought to determine the immune response to malaria infection and the outcome. Cytophilic antibodies have been associated with protection, whereas noncytophilic antibodies against the same epitopes may block the protective activity of the protective ones. To assess the contribution of genetic factors to immunoglobulin G (IgG) subclass responses against conserved epitopes and Plasmodium falciparum blood-stage extracts, we analyzed the isotypic distribution of the IgG responses in 366 individuals living in two differently exposed areas in Burkina Faso. We used one-way analysis of variance and pairwise estimators to calculate sib-sib and parent-offspring correlation coefficients, respectively. Familial patterns of inheritance of IgG subclass responses to defined antigens and P. falciparum extracts appear to be similar in the two areas. We observed a sibling correlation for the IgG, IgG1, IgG2, IgG3, and IgG4 responses directed against ring-infected-erythrocyte surface antigen, merozoite surface protein 1 (MSP-1), MSP-2, and P. falciparum extract. Moreover, a parent-offspring correlation was found for several IgG subclass responses, including the IgG, IgG1, IgG2, IgG3, and IgG4 responses directed against conserved MSP-2 epitopes. Our results indicated that the IgG subclass responses against P. falciparum blood-stage antigens are partly influenced by host genetic factors. The localization and identification of these genes may have implications for immunoepidemiology and vaccine development.