Two consanguineous Qatari siblings presented for evaluation: a 17-4/12-year-old 
male with hypogonadotropic hypogonadism, alopecia, intellectual disability, and 
microcephaly and his 19-year-old sister with primary amenorrhea, alopecia, and 
normal cognition. Both required hormone treatment to produce secondary sex 
characteristics and pubertal development beyond Tanner 1. SNP array analysis of 
both probands was performed to detect shared regions of homozygosity which may 
harbor homozygous mutations in a gene causing their common features of abnormal 
pubertal development, alopecia, and variable cognitive delay. Our patients 
shared multiple homozygous genomic regions; ten shared regions were >1 Mb in 
length and constituted 0.99% of the genome. DCAF17, encoding a transmembrane 
nuclear protein of uncertain function, was the only gene identified in a 
homozygous region known to cause hypogonadotropic hypogonadism. DCAF17 mutations 
are associated with Woodhouse-Sakati syndrome, a rare disorder characterized by 
alopecia, hypogonadotropic hypogonadism, sensorineural hearing loss, diabetes 
mellitus, and extrapyramidal movements. Sequencing of the coding exons and 
flanking intronic regions of DCAF17 in the proband revealed homozygosity for a 
previously described founder mutation (c.436delC). Targeted DCAF17 sequencing of 
his affected sibling revealed the same homozygous mutation. This family 
illustrates the utility of SNP array testing in consanguineous families to 
efficiently and inexpensively identify regions of genomic homozygosity in which 
genetic candidates for recessive conditions can be identified.