[The effects of newborn genetic screening for GJB2 and hearing follow-ups]

To determine the prevalence of GJB2 mutations in newborns and provide clinical experience for newborn genetic screening.

Blood samples of 23 836 newborns in Beijing from March 2012 to December 2013 were screened for hot spot mutations of GJB2 associated with hearing loss. The genetic screening results were comprehensively analyzed with hearing results in genetic counseling.

One or two pathogenic mutations of GJB2 were spotted in 622(2. 61%) individuals. Among them, numbers of newborns with 1 mutation of c. 35deiG,c. 176191 del16,c. 235delC and c. 299300 delAT were 3,26,467 and 120. One compound heterozygote, and 5 homozygotes were also identified. Five hundred and fifty(88. 6%)newborns were followed up by telephones and SMS (short message service) and 325 newborns visit our genetic clinic regularly which were regarded as the research object. In the hearing screening, the referral rate for hearing loss in the first-step screening was 13.8% (45/325), and became 9.2% (30/325) upon retesting. Nine newborns (2. 8%) were diagnosed as hearing loss of different degrees as early as 3 months old,including 6 homozygous/compound heterozygote and 3 heterozygotes.

Patients with GJB2 mutations have various phenotype. Newborns with homozygous/compound heterozygous GJB2 mutations may pass the hearing screening at first. Carriers of GJB2 may also have hearing problems. The combination of genetic and audiological screening can play an important role in deafness detections of infants before key period of speech development.