Homozygosity mapping of Alstrom syndrome to chromosome 2p

Alstrom syndrome is a rare autosomal recessive disorder characterized by pigmentary retinal degeneration, sensorineural hearing loss, childhood obesity, non-insulin-dependent diabetes mellitus, hyperlipidemia and chronic nephropathy. Features occasionally observed include acanthosis nigricans, hypogonadism, hypothyroidism, alopecia, short stature and cardiomyopathy. We report here the results of a linkage study in a large French Acadian kindred, as a first step in identifying the molecular basis of Alstrom syndrome, Evidence of a founder effect made it feasible to use a homozygosity mapping strategy to identify the chromosomal location of the Alstrom gene, In a genome-wide screen, haplotype sharing for a region on chromosome 2 was observed in all affected individuals, Two point linkage analysis resulted in a maximum lod score of 3.84 (theta = 0.00) for marker D25292. By testing additional markers, the disease gene was localized to a 14.9 cM region on chromosome 2p.