BMC Public Health Research article Feasibility of identifying families for genetic studies of birth defects using the National Health Interview Survey Diego F Wyszynski* and Vikki G Nolan BioMed Central Open Access Address: Genetics Program, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, USA Email: Diego F Wyszynski* - dfw@bu.edu; Vikki G Nolan - vnolan@bu.edu * Corresponding author Published: 12 May 2004 BMC Public Health 2004, 4:16 This article is available from: http://www.biomedcentral.com/1471-2458/4/16 Received: 10 September 2003 Accepted: 12 May 2004 © 2004 Wyszynski and Nolan; licensee BioMed Central Ltd. This is an Open Access article: verbatim copying and redistribution of this article are permit- ted in all media for any purpose, provided this notice is preserved along with the article's original URL. Abstract 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. Background During the past decade, there has been significant progress in identifying the genetic basis of many Mende- lian conditions. In February 2003, the Online Mendelian Inheritance in Man catalog reported the localization of 14,206 gene loci, of which 13,311 are autosomal, 792 are X-linked, and 103 are Y-linked or mitochondrial[1]. Some of these have been shown to cause birth defects (i.e., hypohidrotic ectodermal dysplasia, dentinogenesis imperfecta II, Papillon-Lefevre syndrome, Apert syn- drome, aniredia, Van der Woude syndrome, popliteal pterygium, and congenital fibrosis of the extraocular mus- cles). Progress, however, has been substantially slower for the more common disorders that are complex and influ- enced by multiple genes interacting with each other and with environmental factors. For example, the search for the genetic basis of non-syndromic cleft lip with or with- out cleft palate (CL/P) began more than 60 years ago (see the classic work of Fogh-Andersen[2]), but despite a rela- tively high heritability rate for clefts[3], the search for Page 1 of 7 (page number not for citation purposes)