Nonsyndromic 35 delG mutation of the connexin 26 gene associated with deafness in syndromic children: two case reports.
OBJECTIVE
Several genetic diseases, such as velocardiofacial syndrome Del(22q11) and Down syndrome, are associated with hearing impairment.


METHODS
Case reports.


METHODS
The authors reported two cases of hearing-impaired children, one with Del (22q11) and one with Down syndrome, both with bilateral nonevolutive profound sensorineural deafness. Because of unusual features of their deafness and familial history, genetic evaluation was proposed. A homozygous 35delG mutation on the Connexin 26 gene was found in both children (DFNB1 phenotype).


RESULTS
A review of the reported otological features of Del (22q11) and Down syndrome showed that sensorineural deafness is rare and seldom profound. The authors found no evidence for a genetic link between Del(22q11) or Down syndrome and 35delG mutation on the Connexin 26 gene.


CONCLUSIONS
The case reports reveal a coincidental association between DFNB1 and a multiple congenital anomaly syndrome. The clinician must be aware of this type of association to manage genetic counseling, appropriate otological care, and suitable treatment.
Venail
Frédéric
F
Service ENT Department, University Hospital Montpellier, France.
Roux
Anne-Françoise
AF
Pallares-Ruiz
Nathalie
N
Claustres
Mireille
M
Blanchet
Patricia
P
Gardiner
Quentin
Q
Mondain
Michel
M
D002648:Child; D002892:Chromosomes, Human, Pair 22 / Q000235:genetics*; D000072259:Connexin 26; D017630:Connexins / Q000235:genetics*; D019465:Craniofacial Abnormalities / Q000235:genetics*; D004314:Down Syndrome / Q000235:genetics*; D005260:Female; D006319:Hearing Loss, Sensorineural / Q000235:genetics*; D006801:Humans; D008297:Male; D009154:Mutation; D010641:Phenotype; D013577:Syndrome
D017630:Connexins; C000607042:GJB2 protein, human; D000072259:Connexin 26