Oral Clefts with Associated Anomalies: Findings in the Hungarian Congenital Abnormality Registry

BACKGROUND: Over the years, great efforts have been made to record the frequency of orofacial clefts in different populations. However, very few studies were able to account for the etiological and phenotypic heterogeneity of these conditions. Thus, data of cases with syndromic orofacial clefts from large population-based studies are infrequent. METHODS: Clinically recognized and notified syndromes and associations including cleft lip with or without cleft palate and other congenital anomalies were selected from the Hungarian Congenital Abnormality Registry (HCAR) between 1973 and 1982 and prevalence rates were calculated. RESULTS: Of 3,110 cases reported as having orofacial clefts, 653 had multiple congenital abnormalities. Of these, 60 (9.2%) had a known etiology (monogenic: 25 or 3.8%, chromosomal: 31 or 4.7%, teratogenic: 4 or 0.6%). Seventy-three subjects (11.2%) had schisis in addition to the oral cleft. Skeletal anomalies were the most common malformations among cases with cleft lip with/without cleft palate (CL/P) and cleft palate (CP). Disorders of the central nervous system and cardiovascular malformations were also frequently associated. CONCLUSION: Surveillance systems, such as the HCAR, provide useful information about prevalence rates of congenital anomalies in a population. However, in a field where new syndromes are being discovered and classifications regularly updated, these rates should only be accepted as provisional.Massachusetts Center for Birth Defects Research and Prevention of the Massachusetts Department of Public Health; Peer Foundation/Cleft Palate Foundation Etiology Gran

Search for genetic factors predisposing to atherogenic dyslipidemia

BACKGROUND: Atherogenic dyslipidemia (AD) is a common feature in persons with premature coronary heart disease. While several linkage studies have been carried out to dissect the genetic etiology of lipid levels, few have investigated the AD lipid triad comprising elevated serum triglyceride, small low density lipoprotein (LDL) particles, and reduced high density lipoprotein (HDL) cholesterol levels. Here we report the results of a whole-genome screen for AD using the Framingham Heart Study population. RESULTS: Our analyses provide some evidence for linkage to AD on chromosomes 1q31, 3q29, 10q26, 14p12, 14q13, 16q24, 18p11, and 19q13. CONCLUSION: AD susceptibility is modulated by multiple genes in different chromosomes. Our study confirms results from other populations and suggests new areas of potential importance

Empirically derived phenotypic subgroups – qualitative and quantitative trait analyses

BACKGROUND: The Framingham Heart Study has contributed a great deal to advances in medicine. Most of the phenotypes investigated have been univariate traits (quantitative or qualitative). The aims of this study are to derive multivariate traits by identifying homogeneous groups of people and assigning both qualitative and quantitative trait scores; to assess the heritability of the derived traits; and to conduct both qualitative and quantitative linkage analysis on one of the heritable traits. METHODS: Multiple correspondence analysis, a nonparametric analogue of principal components analysis, was used for data reduction. Two-stage clustering, using both k-means and agglomerative hierarchical clustering, was used to cluster individuals based upon axes (factor) scores obtained from the data reduction. Probability of cluster membership was calculated using binary logistic regression. Heritability was calculated using SOLAR, which was also used for the quantitative trait analysis. GENEHUNTER-PLUS was used for the qualitative trait analysis. RESULTS: We found four phenotypically distinct groups. Membership in the smallest group was heritable (38%, p < 1 × 10(-6)) and had characteristics consistent with atherogenic dyslipidemia. We found both qualitative and quantitative LOD scores above 3 on chromosomes 11 and 14 (11q13, 14q23, 14q31). There were two Kong & Cox LOD scores above 1.0 on chromosome 6 (6p21) and chromosome 11 (11q23). CONCLUSION: This approach may be useful for the identification of genetic heterogeneity in complex phenotypes by clarifying the phenotype definition prior to linkage analysis. Some of our findings are in regions linked to elements of atherogenic dyslipidemia and related diagnoses, some may be novel, or may be false positives

Genome-wide screen for heavy alcohol consumption

BACKGROUND: To find specific genes predisposing to heavy alcohol consumption (self-reported consumption of 24 grams or more of alcohol per day among men and 12 grams or more among women), we studied 330 families collected by the Framingham Heart Study made available to participants in the Genetic Analysis Workshop 13 (GAW13). RESULTS: Parametric and nonparametric methods of linkage analysis were used. No significant evidence of linkage was found; however, weak signals were identified in several chromosomal regions, including 1p22, 4q12, 4q25, and 11q24, which are in the vicinity of those reported in other similar studies. CONCLUSION: Our study did not reveal significant evidence of linkage to heavy alcohol use; however, we found weak confirmation of studies carried out in other populations

Feasibility of identifying families for genetic studies of birth defects using the National Health Interview Survey

BACKGROUND: The purpose of this study was to determine whether the National Health Interview Survey is a useful source to identify informative families for genetic studies of birth defects. METHODS: The 1994/1995 National Health Interview Survey (NHIS) was used to identify households where individuals with two or more birth defects reside. Four groups of households were identified: 1) single non-familial (one individual with one birth defect); 2) single familial (more than one individual with one birth defect); 3) multiple non-familial (one individual with more than one birth defect), and 4) multiple familial (more than one individual with more than one birth defect). The March 2000 U.S. Census on households was used to estimate the total number of households in which there are individuals with birth defects. RESULTS: Of a total of 28,094 households and surveyed about birth defects and impairments, 1,083 single non-familial, 55 multiple non-familial, 54 single familial, and 8 multiple familial households were identified. Based on the 2000 U.S. census, it is estimated that there are 4,472,385 households where at least one person has one birth defect in the United States and in 234,846 of them there are at least two affected individuals. Western states had the highest prevalence rates. CONCLUSIONS: Population-based methods, such as the NHIS, are modestly useful to identify the number and the regions where candidate families for genetic studies of birth defects reside. Clinic based studies and birth defects surveillance systems that collect family history offer better probability of ascertainment

Discordant MZ twins With Cleft Lip and Palate: a model for identifying genes in complex traits.

Monozygotic (MZ) twins may be discordant for complex traits due to differential environmental exposure in utero, epigenetic variability in imprinting, X chromosome inactivation, or stochastic effects. Occasionally MZ twins may be discordant for chromosomal and single gene disorders due to somatic mosaicism. For complex traits, which are due to the interactive effects of multiple genes and environmental factors, the affected twin of a discordant MZ pair offers the possibility for identifying somatic mutations in candidate genes. DNA sequencing of candidate genes in discordant MZ twins can identify those rare etiologic mutational events responsible for the different phenotypes since the confounding effects of common single nucleotide polymorphisms are eliminated, as DNA sequences should be identical in MZ pairs. In this report we describe the extensive DNA sequencing of 18 candidate genes in a sample of MZ and dizygotic (DZ) twins with nonsyndromic cleft lip with or without cleft palate. We were unable to identify any somatic differences in approximately 34 Kb of DNA sequenced in 13 MZ pairs, for a total of approximately 900 Kb of sequence comparisons, supporting the hypothesis that nonetiologic posttwinning mutations are rare. While no etiologic variants were identified in this study, sequence comparisons of discordant MZ twins can serve as a tool for identifying etiologic mutations in clefting and other complex traits

Genetic epidemiology: an expanding scientific discipline

Genetic epidemiology is a relatively new discipline that studies the interaction between genetic and environmental factors in the etiology of human diseases. Taking advantage of genetic markers provided by molecular biological research, complex computerized algorithms, and large databases, the field of genetic epidemiology has undergone significant development over the past 10 years. Using concrete examples from recent scientific literature, this article describes the objectives and methodology of genetic epidemiology

La epidemiología genética: disciplina científica en expansión

La epidemiología genética es una disciplina relativamente reciente que estudia la interacción entre los factores genéticos y ambientales que dan origen a las enfermedades del ser humano. Valiéndose de marcadores genéticos desarrollados a través de la biología molecular, de complejos algoritmos almacenados en computadoras y de amplias bases de datos, la epidemiología genética se ha desarrollado notablemente durante los últimos 10 años. El presente artículo describe los objetivos de la epidemiología genética y su metodología, empleando ejemplos concretos tomados de la literatura científica reciente