Phenotype/genotype in congenital central hypoventilation syndrome

Abstract

Abstract Purpose To report and to classify the ocular motility disorders in congenital central hypoventilation syndrome. This rare syndrome, 1 of 200,000 livebirths, is characterized by a lack of ventilation due to defects of autonomic control especially of hypercapnia. Methods We examine in a study 34 children (range 9 days‐old to 15 yo) with congenital central hypoventilation syndrome. They underwent a complete ocular and orthoptic consultation. An informed consent was signed to perform a DNA analysis to precise PHOX‐2B gene mutations. Results Anisocoria, stabismus, eso and exotropia or phoria, ptosis, craniofacial palsy were found and we evaluated disorders considering intrinsic ocular motility and extrinsic ocular motility. We classified ocular anomalies in minor and major types with a score. The phenotype score was established in correlation with genotype. The score is higher in patients with genotype of equal or more 7 ALA mutations and a precise table correlation was established. Conclusion The high incidence of ocular motility disorders may result of neurologic defects of the oculomotor nerves and muscles involving neural crest development. A precise phenotype contributes to an evaluation of the severity of the disease and can also lead to a better reeducation of oculomotor anomalies.