OBJECTIVE: To determine the prevalence of GJB2 mutations in newborns and provide clinical experience for newborn genetic screening. METHOD: 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. RESULT: 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. CONCLUSION 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.
Base Sequence ; Connexin 26 ; Connexins ; genetics ; Deafness ; genetics ; Follow-Up Studies ; Genetic Testing ; Hearing Loss ; genetics ; Hearing Tests ; Heterozygote ; Humans ; Infant ; Infant, Newborn ; Mutation ; Neonatal Screening ; Prevalence

  Objective  Mohr-Tranebjaerg syndrome (MTS) is a rare X-linked neurodegenerative disorder which usually involving hearing impairment, gradual dystonia, and other symptoms. In this study, we perform analyzed the genetic makeup of a family with this rare Mohr-Tranebjaerg syndrome.  Methods  We collected the clinical data of the family, did the whole exome sequencing on the proband Ⅲ6 with a rare mutation, and verified the mutation in another affected family member Ⅲ5 and unaffected members Ⅰ1, Ⅰ2, Ⅱ1, Ⅱ5, Ⅱ7, Ⅱ8, Ⅲ7.  Results  The patients in the family all showed early-onset deafness. More than a couple of affected male members have dystonia with/without mental disorders. Genetic testing results showed the proband Ⅲ6 had a c.133-2delA in TIMM8A (NM_ 004085.3, DDP1), highly likely pathogenic(LP). This variation was detected in affected Ⅲ5 as well as the unaffected females Ⅰ1, Ⅱ5, Ⅱ7.  Conclusions  MTS caused by the rare TIMM8A mutation, the molecular etiology of the family with this rare disease, is highly consistent with the clinical manifestations and segregation. Other than the deafness, other symptoms varied among the affected family members. Genetic diagnosis for such X-linked diseases can also identify female heterozygotes. Genetic and reproduction counseling can help families in the family planning.