Key result
Evaluation of a large kindred identified 6 individuals with definite Usher's syndrome and 4 with deafness only, indicating considerable variation in the expressivity of the mutant gene.
Observational
The mutant gene responsible for Usher's syndrome exhibits considerable variation in clinical expressivity within the same kindred.
Answers are grounded in this paper and cite their sources.
Variable expressivity in Usher syndrome families warrants cautious counseling; leaves open whether isolated deafness represents the same genotype.
The clinical and audiologic findings in carriers and affected matings of a large kindred containing six individuals with definite Usher's syndrome are documented. Comparisons among and within sibships indicate that the same mutant gene may show considerable variation in expressivity. Although four additional deaf individuals were found who had no retinitis pigmentosa or visual impairment, it is still not certain that the range of clinical manifestation of the gene for Usher's syndrome includes deafness with no visual symptoms. Usher's syndrome is an important diagnosis to make because even in the absence of specific therapy, knowledge of impending loss of vision could have an important influence on selection of the most appropriate educational habilitative program.
No takes yet. Share an insight, caveat, or question.
McLeod et al. (1971) conducted an observational in Usher's syndrome. Mutant gene for Usher's syndrome was evaluated on Clinical and audiologic findings (expressivity of the mutant gene). Evaluation of a large kindred identified 6 individuals with definite Usher's syndrome and 4 with deafness only, indicating considerable variation in the expressivity of the mutant gene.
Synapse has enriched 10 related papers. Consider them for comparative context: