Abstract
Purpose: :
To search for mutations in the Norrie diease gene (NDP) in Japanese patients with familial exudative vitreoretinopathy (FEVR) or Norrie disease (ND) and to delineate the mutation–associated clinical features.
Methods: :
Direct sequencing following polymerase chain reaction of all exons of NDP was performed for 61 probands (35 familial and 26 simplex) of FEVR including one familial case presumably of ND, and some of their families. Clinical symptoms among patients with mutations were assessed
Results: :
Three novel and one recurrent mutations in NDP (K54N, R97P, R115L and IVS2–1g>a) were identified in three familial and two sporadic cases (8% = 5/61). The severity of vitreoretinopathy varied among these patients: three probands either with K54N or R115L showed typical features of FEVR, whereas the other two cases with R97P or IVS2–1g>a exhibited severer phenotype i.e., total retinal detachment since neonate. For the proband with R97P mutation, ND was highly suspected because of the family history of mental retardation. In the familial case with K54N mutation, three heterozygous female carriers presented with variable degrees of vascular abnormalities in the periphery of the retina.
Conclusions: :
The mutations in NDP resulted in FEVR or ND with variable expressivity. ND cannot be easily distinguished from FEVR without the presence of systemic symptoms and family history. Building data base for genotype–phenotype correlation offers proper genetic counseling for these ocular disorders.
Keywords: genetics • retinal degenerations: hereditary • mutations