<p><b>OBJECTIVE</b>To investigate the
incidence of hot spot
mutation of PDS
gene by
genetic screening testing
method in Chifeng City,
Inner Mongolia . The feasibility and
effectiveness of
genetic screening method in finding enlarged
vestibular aqueduct syndrome were confirmed by
temporal bone CT scan.</p><p><b>
METHODS </b>
DNA were extracted from peripheral
blood of 141
students of Chifeng Deaf and Dumb
school . PDS IVS7-2 A-G
mutation , the most common PDS
mutation in
Chinese population , was analyzed by direct sequencing for PDS
exon 7,
exon 8 with
intron 7. The individuals found with homozygous or heterozygous PDS IVS7-2 A-G
mutation were given further temporal CT scan, ultrasound scan of
thyroid and
thyroid hormone assays. The results of PDS
genetic screening and
temporal bone CT scan were compared with each other.</p><p><b>RESULTS</b>The sequencing results revealed twenty cases
carrying PDS IVS7-2 A-G
mutation , of whom nine cases were homozygous
mutation and eleven cases were heterozygous
mutation . Eighteen cases underwent
temporal bone CT scan except two cases that left the
school due to other
health problem. Sixteen cases were confirmed to be enlarged
vestibular aqueduct syndrome (EVAS) by CT scan and the shape and function of
thyroid were clinically normal by ultrasound scan of
thyroid and
thyroid hormone assays, respectively.</p><p><b>CONCLUSIONS</b>The
patients suffered from EVAS can be diagnosed by the
screening for the PDS hot spot
mutation which has unique advantage in
epidemiologic study in large scale deaf
population . The
preliminary data of this study suggested relatively high
incidence of EVAS in Chifeng area.</p>