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No evidence for triallelic inheritance of MKKS/BBS loci in Amish Mckusick–Kaufman syndrome
Author(s) -
Nakane Takaya,
Biesecker Leslie G.
Publication year - 2005
Publication title -
american journal of medical genetics part a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.064
H-Index - 112
eISSN - 1552-4833
pISSN - 1552-4825
DOI - 10.1002/ajmg.a.30593
Subject(s) - genetics , biology , penetrance , allele , bardet–biedl syndrome , genotyping , gene , genotype , phenotype
It has been hypothesized that two mutations in one gene are not sufficient and that three mutations between two genes are required for penetrance in some cases of Bardet–Biedl syndrome (the so‐called “triallelic inheritance” model). McKusick–Kaufman syndrome (MKS) is allelic to one form of Bardet–Biedl syndrome (BBS). We describe an Amish family with MKS, where three children were affected with homozygous MKKS ( BBS6 ) mutations (H84Y and A242S on both alleles), their father was a carrier, and their mother was homozygous for the same MKKS mutations, but she was non‐penetrant. Genotyping and/or sequencing of BBS1 , BBS2 , BBS3 , BBS4 , BBS5 , BBS7 , and BBS8 excluded “triallelic inheritance” for each gene either by an incompatible inheritance pattern or an absence of mutations in the coding region and the intronic splice junctions of these genes. We conclude that the “triallelic” model does not explain the incomplete penetrance of MKS. Published 2005 Wiley‐Liss, Inc.