Haddad Syndrome with 27 Polyalanine Repeats in PHOX2B Gene in a Korean Infant / 대한주산의학회잡지

ABSTRACT

Haddad syndrome is an extremely rare disorder which combines congenital central hypoventilation syndrome (CCHS) and Hirschsprung's disease. Several reports have demonstrated that CCHS was related to mutation of the PHOX2B gene. We report here a newborn male infant with apnea and bowel obstruction. He has been diagnosed with combined congenital central hypoventilation syndrome and Hirschsprung's disease, and had 27 polyalanine repeats in the PHOX2B gene. Two cases of Haddad syndrome with identified PHOX2B gene mutation have been recently reported in Korea. Both of them had extended alleles containing 26 polyalanine repeats. It is known that increased number of polyalanine repeat mutations is associated with a more severe clinical phenotype. The baby reported here had 27 alanine repeats (i.e. one more than the previously reported cases in Korea) and ganglion cells could be found only in the distal 70 cm of his small bowel.