Background: Brittle cornea syndrome (BCS) is a rare autosomal recessive connective tissue disease characterized by variable combinations of corneal thinning and fragility, corneal ruptures either spontaneously or after minor trauma, blue sclerae, keratoconus, keratoglobus, and high myopia. So far, mutations in 2 genes, PRDM5 and ZNF469, have been associated with BCS. The purpose of this study is to describe novel mutations in the PRDM5 gene in patients with BCS.
Methods and results: Using homozygosity mapping with single-nucleotide polymorphism markers followed by whole-exome sequencing, we identified a novel homozygous splice site variant (c.93+5G>A) in the PRDM5 gene in a consanguineous Pakistani family with 4 affected individuals. Reverse transcription-polymerase chain reaction analysis from lymphocyte-derived RNA failed to reveal any exon skipping because of this splice site variant. A homozygous variant (c.11T>G; p.Gln4Pro) in SEC24D also segregated with the disease in this particular family. One previously known mutation (c.974del; p.Cys325LeufsX2) was identified in a sporadic patient with BCS from Serbia.
Conclusions: The current study revealed a novel mutation in the PRDM5 gene in a BCS family and recurrent mutation in a sporadic BCS patient. A variant in the SEC24D gene also segregated in the BCS family, although its role in the disease remains unclear.