Value of pre-gestational deafness-related mutation screening for the prevention and intervention of congenital deafness / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To assess the value of pre-gestational deafness-related mutation screening for the prevention and intervention of congenital deafness.</p><p><b>METHODS</b>In this study, 2168 couples with normal hearing were screened for common mutations associated with congenital deafness using real-time fluorescence quantitative PCR. The mutations have included GJB2 c.235delC and c.299_300delAT, SLC26A4 c.2168A>G and c.IVS7-2A>G, and mtDNA 12SrRNA c.1494C>T and c.1555A>G. For couples who have both carried heterozygous mutations of the same gene, genetic counseling and prenatal diagnosis were provided.</p><p><b>RESULTS</b>Among of the 4 336 individuals, 178 (4.06%) were found to carry a mutation. Mutation rate for c.235delC and c.299_300delAT of GJB2 gene, c.IVS7-2 A>G and c.2168 A>G of SLC26A4 gene, c.1555 A>G and c.1494 C>T of DNA 12S rRNA gene were 0.91%, 0.20%, 0.68%, 0.11%, 0.1% and 0.01%, respectively. For six couples who have both carried mutations of the same gene, all fetuses showed a normal karyotype, while DNA sequencing indicated that two fetuses have carried homozygous c.235delC mutation of the GJB2 gene, one carried a heterozygous c.235delC mutation of the GJB2 gene, one carried heterozygous mutation of GJB2 gene (c.299_300delAT), and two have carried a heterozygous mutation of c.IVS7-2A>G of the SLC26A4 gene.</p><p><b>CONCLUSION</b>Pre-gestational screening for deafness gene mutation can facilitate avoidance the birth of affected children and has a great clinical value for the prevention and intervention of birth defect.</p>

Combined hearing and deafness gene mutation screening of 11,046 Chinese newborns / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To evaluate the efficacy of combined newborn hearing screening and deafness-related mutation screening.</p><p><b>METHODS</b>Eleven thousand and forty-six newborn babies were screened with otoacoustic emission, automatic auditory brainstem response and genetic testing using a standard protocol. Common mutations of three deafness-related genes have included GJB2 (c.235delC, c.299-300delAT), mtDNA 12srRNA (c.1494C>T, c.1555A>G) and SLC26A4 (c.2168A>G, c.IVS7-2A>G).</p><p><b>RESULTS</b>The detection rate for hearing loss in the first-step screening was 0.81% (90/11,046). 513 individuals were found to carry one or two mutant alleles, which gave a carrier rate of 4.64% (513/11,046). Five hundred and eighty-four newborns were positive for hearing screening and genetic screening. Among these, 19 have failed both tests, 71 have failed hearing screening, and 494 have failed genetic screening. The combined hearing and genetic screening has given a positive rate of 5.29%.</p><p><b>CONCLUSION</b>Neither hearing screening nor genetic screening is sufficient to identify individuals susceptible to auditory disorders. Combined used of these methods can improve the rate of detection.</p>