Having identified a disease-associated @entity8695 mutation in a @entity1 with @entity6391 ( @entity6391 ), the issue is to address the question of whether to offer genetic testing to at-risk family members. Two members of a South African (SA) family, one of whom suffers from @entity6391 , as well as 54 unrelated SA @entity6391 @entity1 from the same population group were investigated using single-stranded conformational polymorphism analysis followed by DNA sequencing. A rare homozygous mutation at the intron-exon boundary of exon 4 in the @entity8695 gene was identified in the proband. One of his siblings was found to be heterozygous for the same mutation. The mutation was not detected in the 54 unrelated SA @entity6391 @entity1 examined, 11 of whom were sporadic cases. A low incidence of @entity6391 amongst heterozygous carriers of this mutation has been reported; however, in the past it has been unclear whether the mutation has an effect in single copy or dual copy. To the best of our knowledge, this is the first time that this mutation has been reported as homozygous in an affected individual, thereby resolving the issue and confirming that it is a recessive disease-associated mutation. This is also the first @entity989 -causing @entity8695 mutation that has been identified in Southern Africa. Analysis of the extended pedigree indicated obligate heterozygous carriers of the mutation, without obvious signs of @entity227 in early adulthood. The extent to which potential heterozygous carriers should be pursued and clinically examined is discussed and the question is addressed as to whether to inform the family of these molecular findings.

A rare homozygous XXXX splice-site mutation: the issue of when and whether to offer presymptomatic testing.

@entity1 :: ('9606', 'Species') :: ['patients', 'patient'] @entity227 :: ('MESH:D014786', 'Disease') :: ['visual impairment'] @entity8695 :: ('6010', 'Gene') :: ['rhodopsin'] @entity6391 :: ('MESH:D012174', 'Disease') :: ['retinitis pigmentosa', 'RP'] @entity989 :: ('MESH:D012164', 'Disease') :: ['autosomal recessive RP disease']
@entity8695 :: (6010,Gene) :: ['rhodopsin']
