CHD7 mutations and CHARGE syndrome in semicircular canal dysplasia.

OBJECTIVE

To determine whether patients with semicircular canal dysplasia have mutations in CHD7.

BACKGROUND

CHARGE syndrome is a nonrandom clustering of congenital anomalies, including ocular coloboma, heart defects, choanal atresia or stenosis, retarded growth and development, genital hypoplasia, and inner and outer ear anomalies including deafness. Semicircular canal dysplasia has been included as a major diagnostic criterion for CHARGE syndrome. Mutations in the gene CHD7 on chromosome 8q12.1 are a major cause of CHARGE syndrome, but the extent to which patients with semicircular canal dysplasia have CHD7 mutations is not fully understood.

STUDY

DESIGN

Cross-sectional analysis of CHD7 in 12 patients with semicircular canal dysplasia and variable clinical features of CHARGE syndrome.

RESULTS

We identified 6 CHD7 mutations, 5 of which occurred in patients who fulfilled Verloes' diagnostic criteria for typical CHARGE syndrome, and three of which were previously unreported. Of the 3 remaining CHD7 mutation-positive patients, one had atypical CHARGE by diagnostic criteria. Four MRI records were available, which revealed 2 patients with cochlear nerve aplasia and 1 patient with Chiari 1 malformation.

CONCLUSION

These data provide additional evidence that CHD7 mutations are a significant cause of semicircular canal atresia in children with full or partial CHARGE syndrome.