Two families from New England with usher syndrome type IC with distinct haplotypes.
OBJECTIVE
To search for patients with Usher syndrome type IC among those with Usher syndrome type I who reside in New England.


METHODS
Genotype analysis of microsatellite markers closely linked to the USH1C locus was done using the polymerase chain reaction. We compared the haplotype of our patients who were homozygous in the USH1C region with the haplotypes found in previously reported USH1C Acadian families who reside in southwestern Louisiana and from a single family residing in Lebanon.


RESULTS
Of 46 unrelated cases of Usher syndrome type I residing in New England, two were homozygous at genetic markers in the USH1C region. Of these, one carried the Acadian USH1C haplotype and had Acadian ancestors (that is, from Nova Scotia) who did not participate in the 1755 migration of Acadians to Louisiana. The second family had a haplotype that proved to be the same as that of a family with USH1C residing in Lebanon. Each of the two families had haplotypes distinct from the other.


CONCLUSIONS
This is the first report that some patients residing in New England have Usher syndrome type IC. Patients with Usher syndrome type IC can have the Acadian haplotype or the Lebanese haplotype compatible with the idea that at least two independently arising pathogenic mutations have occurred in the yet-to-be identified USH1C gene.
Ocular Molecular Genetics Institute, Massachusetts Eye and Ear Infirmary, 243 Charles St., Boston, MA 92114, USA.
M M
MM
DeAngelis
T L
TL
McGee
B J
BJ
Keats
R
R
Slim
E L
EL
Berson
T P
TP
Dryja
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins / Q000235:genetics*; D018797:Cell Cycle Proteins; D003598:Cytoskeletal Proteins; D004252:DNA Mutational Analysis; D003638:Deafness / Q000145:classification / Q000151:congenital / Q000208:ethnology / Q000235:genetics*; D005260:Female; D008040:Genetic Linkage / Q000235:genetics; D006239:Haplotypes; D006801:Humans; D008297:Male; D018895:Microsatellite Repeats; D009511:New England / Q000453:epidemiology; D010375:Pedigree; D012174:Retinitis Pigmentosa / Q000145:classification / Q000208:ethnology / Q000235:genetics*; D013577:Syndrome
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D003598:Cytoskeletal Proteins; C118970:USH1C protein, human