Obesity in heterozygous carriers of the gene for the Bardet‐Biedl syndrome

Abstract

Obesity and renal failure are common manifestations in the autosomal recessive Bardet-Biedl (BB) syndrome. Because obesity and hypertension have been reported frequently in non-homozygous relatives of BB patients, we hypothesized that BB heterozygotes are predisposed to these conditions. Clinical information was collected from 34 patients of BB homozygotes, who are obligate heterozygotes. The proportion of severely overweight fathers (26.7%) was significantly higher than that in comparably aged United States white males (8.9%). We conclude that the BB gene may predispose male heterozygous carriers to obesity. If BB heterozygotes are 1% of the general population, we estimate that approximately 2.9% of all severely overweight white males carry a single BB gene. The BB parents of both sexes were also significantly taller than U.S. white men and women of comparable age.

Bardet–Biedl syndrome 1 genotype and obesity in the Newfoundland population

“…It had been suggested previously that carriers of a BBS mutation are predisposed to obesity. 20,21 The Newfoundland population as a whole has an increased incidence of BBS, 24 which is not the result of a single founder effect, and this has been called the 'Newfoundland Paradox'. 32 It has been proposed that one of the reasons for this increase of BBS in the Newfoundland population is past selection for an increased capacity for carriers of a BBS mutation (heterozygoytes) to store fat under adverse environmental conditions.…”

“…In BBS adults, obesity is usually associated with the trunk and proximal limbs and less frequently the face, 18 but it has also been described as diffuse and nonspecific in distribution during early life. 19 Croft et al 20,21 compared affected individuals with obligate carriers and first-degree relatives in BBS families and raised the possibility that BBS heterozygotes are predisposed to obesity. Indeed, they estimated that approximately 3% of all severely overweight white males in the USA carry a single BBS gene.…”

“…Indeed, they estimated that approximately 3% of all severely overweight white males in the USA carry a single BBS gene. 21 BBS is a relatively rare disorder with a prevalence that varies from one in 125 000 in the United Kingdom 22 to one in 160 000 in Switzerland. 23 The Newfoundland population is enriched for BBS with a prevalence of approximately one in 18 000.…”

Bardet–Biedl syndrome

“…26 Carriers of BBS do not appear to be at increased risk of hypertension or diabetes, 4,10 although conflicting evidence exists regarding the possible increased risk of obesity in carriers. 4,10,27,28 An increase in renal cancers and malformations, 29 as well as retinal dysfunction, 30 has been reported in obligate carriers.…”

Association between BBS6/MKKS gene polymorphisms, obesity and metabolic syndrome in the Greek population

“…There is evidence that heterozygous carriers of BBS mutations are more obese than non-carriers, without displaying other features characteristic of the syndrome. 6 One of the BBScausing genetic loci is the BBS6 gene, alternatively called MKKS (accession no. gi:27501067).…”