Clustering and frequency of mutations in the retinal guanylate cyclase (GUCY2D) gene in patients with dominant cone-rod dystrophies

Editor—A case of Down syndrome, total gut Hirschsprung disease (HSCR), and segmental hypopigmentation is described in a neonate presenting with bowel obstruction. In addition to having trisomy 21, this patient was homozygous for a novel mutation in the endothelin B receptor ( EDNRB ) gene. A term female infant with karyotype 47,XX,+21 presented on day 3 of life with bowel obstruction. She was of Somali origin and had large areas of segmental hypopigmentation affecting the left side of the face and trunk, the left upper limb, including the hair follicles, and had white scalp hair. At laparotomy she had an annular pancreas, duodenal web, and inspissated meconium in the ileum and colon, for which she underwent a duodenoduodenostomy. Histology of the rectal biopsy and appendix was inconclusive at this stage. Intestinal obstruction persisted and on day 20 she underwent a further laparotomy, which showed breakdown of the original anastomosis. Intraoperative frozen sections showed complete aganglionosis throughout the entire large and small …