Usher syndrome: clinical findings and gene localization studies.
The issue of genetic heterogeneity is a critical problem in the localization of the gene(s) for Usher syndrome. Based on the data obtained on families studied to date, the differences between type I and type II Usher syndrome appear quite distinct with regard to auditory and vestibular function. Although the majority of families can be confidently diagnosed as typical type I or type II, clinical investigations revealed four families with findings that did not fit into either of the two more common subtypes. These findings emphasize the critical importance of an in-depth clinical analysis concomitant with the linkage investigation to assure accurate subtyping of Usher syndrome. Based on an analysis of only those families with definite type I or type II Usher syndrome, approximately 17% of the genome can be excluded as a potential site of the gene for type I, and 14% can be excluded as the site for the type II gene. This study will continue until the Usher gene(s) is successfully localized.
Kimberling
W J
WJ
Boys Town National Institute of Communication Disorders in Children, Omaha, NE 68131.
Möller
C G
CG
Davenport
S L
SL
Lund
G
G
Grissom
T J
TJ
Priluck
I
I
White
V
V
Weston
M D
MD
Biscone-Halterman
K
K
Brookhouser
P E
PE
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D004247:DNA / Q000032:analysis; D005260:Female; D008040:Genetic Linkage; D006319:Hearing Loss, Sensorineural / Q000235:genetics*; D006801:Humans; D008607:Intellectual Disability / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D010375:Pedigree; D012150:Polymorphism, Restriction Fragment Length; D012174:Retinitis Pigmentosa / Q000235:genetics*; D013577:Syndrome; D014724:Vestibular Function Tests
D004247:DNA