Abstract
Purpose: :
To investigate reduced bone mineral density (BMD) in patients with familial exudative vitreoretinopathy (FEVR) and underlying mutations in FEVR-causing genes.
Methods: :
In a panel of FEVR families for which coding exons of known causing genes (FZD4, LRP5 and NDP) have been sequenced, forty-three patients were evaluated for BMD using dual energy x-ray absorptiometry. BMD was converted to an SD score (z-score) appropriated for gender-, age- and racially matched control subjects (Japanese).
Results: :
Of the 43 patients, 26 (60%) had BMD of z < -1.0 and 9 (21%) had that of z < -1.5. Of the 9 patients, four patients presented with autosomal dominant mode of inheritance, of which two had FZD4 mutations (z=-4.0 and -1.9), one had LRP5 mutation (z=-2.5), and one carried mutations in both FZD4 and LRP5 (z=-2.1). One patient was an autosomal recessive FEVR with compound heterozygous mutations in LRP5 (z=-3.3). Two patients were X-linked FEVR who carried NDP mutation hemizygously (z=-2.1 and -1.7). One was a sporadic FEVR with no mutations (z=-2.6).
Conclusions: :
Some FEVR patients carrying mutations in FZD4 or NDP tended to have reduced BMD as indicated for mutations in LRP5. This study suggests skeletal pathology is a sign of a fraction of FEVR. The underlying genetic defects may be more heterogeneous than previously thought.
Keywords: retinal degenerations: hereditary • mutations • degenerations/dystrophies