Preferred Label : Usher syndrome, type I;
Symbol : USH1;
CISMeF acronym : USH1A; USH1B; USH1; US1;
Type : Phenotype, molecular basis known;
Alternative titles and symbols : Retinitis pigmentosa and congenital deafness; US1;
Included titles and symbols : Usher syndrome, type ib; Usher syndrome, type ia; Usher syndrome, type I, french variety; USH1B; USH1A;
Description : Usher syndrome type I is an autosomal recessive condition characterized by profound
congenital hearing impairment with unintelligible speech, early retinitis pigmentosa
(usually evident within the first decade), and constant vestibular dysfunction. Type
I is distinguished from type II (276901) on the basis of severity of hearing loss
and the extent of vestibular involvement. Type I patients are profoundly deaf, whereas
type II patients are 'hard of hearing.' Vestibular function is defective in type I
patients, whereas type II patients have normal vestibular function (Moller et al.,
1989). Patients with type III (USH3; 276902) have progressive hearing loss. - Genetic
Heterogeneity of Usher Syndrome Type I USH type I is genetically heterogeneous. USH1C
(276904), the 'Acadian variety,' is caused by mutation in harmonin (605242), on 11p15.1.
USH1D (601067) and USH1F (602083) are caused by mutation in the cadherin-23 (CDH23;
605516) and protocadherin-15 (PCDH15; 605514) genes, respectively; both of these genes
map to 10q21-q22. USH1G (606943) is caused by mutation in the SANS gene (607696),
on 17q24-q25. USH1E (602097) maps to 21q21, USH1H (612632) maps to 15q22-q23, USH1J
(614869) is caused by mutation in the CIB2 gene (605564) on 15q24, and USH1K (614990)
maps to chromosome 10p11.21-q21.1. A form of USH type I in which affected members
carried heterozygous mutations in both CDH23 and PCDH15 has been reported (USH1D/F;
see 601067), thus supporting a digenic model for some individuals with this phenotype.
Gerber et al. (2006) presented evidence that the form of USH1 previously called USH1A,
or the 'French variety,' and mapped to chromosome 14 does not in fact exist; mutations
in the MYO7A gene were found in most of these families, and in others the phenotype
was found to map to other loci. Ahmed et al. (2003) reviewed the molecular genetics
of Usher syndrome and indicated that at least 12 loci had been identified as underlying
the 3 different clinical subtypes.;
Inheritance : Autosomal recessive;
Molecular basis : Caused by mutation in the myosin VIIA gene (MYO7A, 276903.0001);
Prefixed ID : #276900;
Origin ID : 276900;
UMLS CUI : C1568247;
Automatic exact mappings (from CISMeF team)
- Broader ORDO disease(s)
- Currated CISMeF NLP mapping
- DO Cross reference
- Genes related to phenotype
- HPO term(s)
- ORDO concept(s)
- Semantic type(s)
- UMLS correspondences (same concept)
- Validated automatic mappings to BTNT
