A Genetic Counseling of a Family with the Night Blindness

Abstract

Abstract: : Purpose: We performed an elaborate clinical examination, DNA diagnosis and genetic counseling in a family complaining of the night blindness. Methods: A 12-year-old female, proband, was introduced to our hospital suspecting retinitis pigmentosa. Her mother, 19-year-old brother and 18-year-old sister also come to our hospital because all three complaining of night blindness. Results: Fundus finding and visual field examination showed that the mother suffered from fundus albipunctatus and the proband, brother and sister suffered from retinitis pigmentosa. Full field electroretinogram (ERG) recording showed markedly reduced scotopic response which was recovered after 120 minutes dark adaptation in the mother and an extinguish single flash response in three children. The RDH5 gene was analyzed in these four individuals with the informed consent. A heterogeneous base change mutation, nt928 C to GAAG was detected in the proband and the mother. However, no other mutation was detected in another allele of the other exons and surrounding area. No mutation of the RDH5 gene was detected in the brother and the sister. Conclusions: Although the further study is now on going, the causative mutation of night blindness in three children is suspected to be different from that of the mother.

Keywords: genetics • retinal degenerations: hereditary • electroretinography: clinical