Localization of the gene for familial partial lipodystrophy (Dunnigan variety) to chromosome 1q21-22

Abstract

Obesity is strongly implicated in the pathophysiology of insulin resistance, diabetes mellitus and dyslipidemia. The mechanisms, however, by which obesity causes these complications are not known. The study of single-gene disorders affecting adipose tissue may elucidate some of the mechanisms involved in these processes. Familial partial lipodystrophy, Dunnigan variety, (FPLD, OMIM 308980) is an autosomal-dominant condition characterized by marked loss of subcutaneous adipose tissue affecting the trunk and extremities but with excess fat deposition in the head and neck areas. Affected individuals show an increased preponderance of insulin resistance, diabetes mellitus, dyslipidemia and acanthosis nigricans. The genetic basis of FPLD is unknown. We carried out a genome-wide scan with a set of highly polymorphic short tandem-repeats (STR) in individuals from five well-characterized pedigrees and mapped the FPLD locus to chromosome 1q21-22. The maximum two-point lod score obtained with a highly polymorphic microsatellite at D1S2624 at theta(max)=0 was 5.84. Multipoint-linkage analysis yielded a peak lod score of 8.25 between D1S305 and D1S1600. There was no evidence for genetic heterogeneity (alpha=1) in the pedigrees.