A known heterozygous missense variant (c.3260C>T, p.(Ser1087Leu)) in the SNRNP200 gene was identified in the index patient of family A while a novel homozygous missense mutation (c.1634G>A, p.(Arg545His)) was found in the index patient of family B. Nyctalopia and photophobia were reported by 6/6 and 2/6 patients, respectively.
Since all patients with BRESEK/BRESHECK syndrome are male, and X-linked syndrome of ichthyosis follicularis with atrichia and photophobia is sometimes associated with several features of BRESEK/BRESHECK syndrome such as intellectual disability, vertebral and renal anomalies, and Hirschsprung disease, we analyzed the causal gene of ichthyosis follicularis with atrichia and photophobia syndrome, MBTPS2, in the present patient and identified an p.Arg429His mutation.