title: Brachydactyly type B: clinical description, genetic mapping to chromosome 9q, and evidence for a shared ancestral mutation.
abstract: Autosomal dominant brachydactyly type B (BDB) is characterized by nail aplasia with rudimentary or absent distal and middle phalanges. We describe two unrelated families with BDB. One family is English; the other family is Canadian but of English ancestry. We assigned the BDB locus in the Canadian family to an 18-cM interval on 9q, using linkage analysis (LOD score 3.5 at recombination fraction [theta] 0, for marker D9S938). Markers across this interval also cosegregated with the BDB phenotype in the English family (LOD score 2.1 at straight theta=0, for marker D9S277). Within this defined interval is a smaller (7.5-cM) region that contains 10 contiguous markers whose disease-associated haplotype is shared by the two families. This latter result suggests a common founder among families of English descent that are affected with BDB.
authors.affiliation: Department of Genetics and Center for Human Genetics, Case WesternReserve University School of Medicine and University Hospitals of Cleveland, Cleveland, OH, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Gong
authors.forename: D
authors.initials: D
authors.lastname: Chitayat
authors.forename: B
authors.initials: B
authors.lastname: Kerr
authors.forename: T
authors.initials: T
authors.lastname: Chen
authors.forename: R
authors.initials: R
authors.lastname: Babul-Hirji
authors.forename: A
authors.initials: A
authors.lastname: Pal
authors.forename: M
authors.initials: M
authors.lastname: Reiss
authors.forename: M L
authors.initials: ML
authors.lastname: Warman
mesh_terms: D030201:Activin Receptors, Type I; D002874:Chromosome Mapping; D002899:Chromosomes, Human, Pair 9; D005260:Female; D005385:Fingers / Q000002:abnormalities*; D005532:Foot Deformities, Congenital / Q000235:genetics* / Q000503:physiopathology; D005799:Genes, Dominant; D006228:Hand Deformities, Congenital / Q000235:genetics* / Q000503:physiopathology; D006239:Haplotypes; D006801:Humans; D008297:Male; D009154:Mutation; D010375:Pedigree; D017346:Protein Serine-Threonine Kinases / Q000235:genetics*; D000077293:Receptor, Transforming Growth Factor-beta Type I; D018125:Receptors, Transforming Growth Factor beta / Q000235:genetics*; D014034:Toes / Q000002:abnormalities*