More than meets the eye: expanding and reviewing the clinical and
mutational spectrum of brittle cornea syndrome
Abstract
Brittle cornea syndrome (BCS) is a rare autosomal recessive disorder
characterized by corneal thinning and fragility, leading to corneal
rupture, the main hallmark of this disorder. Non-ocular symptoms include
hearing loss, but also signs of connective tissue fragility, placing it
in the Ehlers-Danlos syndrome (EDS) spectrum. It is caused by biallelic
pathogenic variants in ZNF469 or PRDM5, which presumably encode
transcription factors for extracellular matrix components. We report the
clinical and molecular features of nine novel BCS families, four of
which harbor variants in ZNF469 and five in PRDM5. We also performed a
genotype and phenotype-oriented literature overview of all (N=85)
reported patients with ZNF469 (N=53) and PRDM5 (N=32) variants.
Musculoskeletal findings may be the mean reason for referral, and often
raise suspicion of another heritable connective tissue disorder such as
kyphoscoliotic EDS, osteogenesis imperfecta or Marfan syndrome,
especially when corneal rupture has not yet occurred. Our findings
highlight the multisystemic nature of BCS and validate its inclusion in
the EDS classification. Importantly, gene panels for heritable
connective tissue disorders should include ZNF469 and PRDM5 to allow for
timely diagnosis and appropriate preventive measures for this rare
condition.