EP10.03: A case of unilateral choanal atresia

Abstract

Choanal atresia (CA) is a congenital obstruction of the posterior nasal apertures. Unilateral CA is more common than bilateral. CA can be sporadic in 33 % or associated with a recognised syndrome in 67 %. CHARGE (coloboma, heart defect, choanal atresia, retarded growth, genitourinary abnormalities and ear anomalies) syndrome is the most common diagnosis. Mutations in the gene CHD7 on chromosome 8q12.1 are a major cause of CHARGE syndrome. Other congenital anomalies associated with CA are Treacher Collins syndrome, Crouzon's disease and Apert syndrome. In the general population, the incidence of choanal atresia is approximately 1 in 5000-7000 live births. We present a case of a 34-year-old primigravida who attended our centre for a routine anomaly scan at 20 weeks of pregnancy. Detailed examination revealed the asymmetry of nose and slightly asymmetric face. No other fetal anatomic abnormalities were detected. We suspected a unilateral choanal atresia, which was confirmed at birth. Amniocentesis showed normal karyotype. In subsequent analysis of the CHD7 gene, 23 exons were sequenced and no mutations were found. Currently, the examination of exons 24-38 is ongoing. Postnatal opthalmologic examination revealed coloboma of the iris, choroid and optic nerve and the cataract of the left eye. A brain MRI displayed a frontonasal encephalocele. CA is not usually described in prenatal reports. This case show that CHARGE syndrome should be a differential diagnosis when choanal atresia is identified prenatally.