Since the 1.3 Mb deletion we identified encompasses the ABCA5 locus, and both sporadic and autosomal recessive CGHT patients possess excessive overgrowth of terminal hairs, we next investigated the possibility that the second allele in the sporadic CGHT case may harbor a mutation in the ABCA5 gene. Here, ABCA5 is linked to gingival fibromatosis-hypertrichosis syndrome.