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Later-onset congenital central hypoventilation syndrome due to a heterozygous 24-polyalanine repeat expansion mutation in the PHOX2B gene.

Research paper by Gabriela M GM Repetto, Raul J RJ Corrales, Selim G SG Abara, Lili L Zhou, Elizabeth M EM Berry-Kravis, Casey M CM Rand, Debra E DE Weese-Mayer

Indexed on: 19 Sep '08Published on: 19 Sep '08Published in: Acta Paediatrica



Abstract

to describe a family with later onset congenital central hypoventilation syndrome (LO-CCHS) and heterozygosity for a 24-polyalanine repeat expansion mutation in the PHOX2B gene, rendered phenotypically apparent with exposure to anesthetics.An otherwise healthy 2.75-year-old boy presented with alveolar hypoventilation after adenoidectomy and tonsillectomy for obstructive sleep apnea, requiring invasive ventilatory support during sleep. He had a heterozygous 24-polyalanine repeat expansion in the PHOX2B gene (20/24 genotype), a genotype that has not been previously described in association with CCHS or LO-CCHS symptoms. Clinical findings in members of the family with the same 20/24 genotype ranged from asymptomatic to prolonged sedation after benzodiazepines.CCHS should be suspected in individuals presenting with unexplained hypoventilation and/or seizures after anesthetics or sedatives. This is the first report of LO-CCHS in a kindred with the PHOX2B 20/24 genotype. The incomplete penetrance observed in this family suggests a gene-environment interaction.