Clinical assessment and genomic landscape of a consanguineous family with three Kallmann syndrome descendants.

Although some genes that cause Kallmann syndrome (KS) have been identified by traditional linkage analysis and candidate gene techniques, the syndrome's molecular etiology in the majority of patients remains poorly understood. In this paper, we present the clinical assessments of a consanguineous Han Chinese family with three KS descendants. To understand the molecular etiology of KS from a genome-wide perspective, we investigated the genome-wide profile of structural variation in this family using the Affymetrix Genome-Wide Human SNP Array 6.0 platform. The results revealed that the three affected individuals had common copy number variants (microdeletions) on chromosomes 1p21.1, 2q32.2, 8q21.13, 14q21.2 and Xp22.31. Moreover, the copy number variants on Xp22.31 were located in the intron of KAL1, which causes X-linked KS. Two PCR assays were performed on these regions to validate the results obtained using the chips. In addition, genomic microdeletions in this region were verified in one of 29 Han Chinese sporadic KS cases and one of four other family cases, but not in 26 Han Chinese sporadic normosmic idiopathic hypogonadotropic hypogonadism cases and 100 unrelated Han Chinese normal controls. Our results provide a novel insight into the relative contributions of certain copy number variants to KS's molecular etiology and generate a list of interesting candidate regions for further studies.