BACKGROUND: Ichthyosis follicularis, atrichia, and photophobia (IFAP) syndrome 
is a rare congenital disorder. Missense mutations in the membrane-bound 
transcription factor protease, site 2 (MBTPS2) gene have recently been 
identified in patients with IFAP.
OBJECTIVE: To determine whether Chinese patients with IFAP have MBTPS2 
mutations.
METHODS: We observed a large IFAP pedigree of 5 generations in a Chinese family 
and performed MBTPS2 molecular analysis.
RESULTS: The male proband was severely affected. He presented with 
hyperextensibility of the interphalangeal joints of the fingers in addition to 
previously reported clinical manifestations. Clinically affected female patients 
had hairless patches on the scalp, ichthyosiform skin changes, hypotrichosis, 
hyperkeratosis, nail dystrophy, and brown scaly plaques, some of which were 
arranged in a linear pattern following the lines of Blaschko. Molecular analysis 
identified a novel missense mutation in exon 11 and confirmed cosegregation of 
the missense mutation with the disease in this family.
LIMITATIONS: It is unclear whether hyperextensibility of the fingers was 
nosologically related to IFAP syndrome or was a coincidental finding.
CONCLUSION: This report provides further evidence for the genetic basis of IFAP 
syndrome and enlarges the phenotypic spectrum and number of MBTPS2 mutations. We 
confirm that MBTPS2 mutations cause IFAP in patients of Chinese origin.