2 CASES OF 5Q DELETIONS IN PATIENTS WITH FAMILIAL ADENOMATOUS POLYPOSIS - POSSIBLE LINK WITH CAROLIS-DISEASE

Two cases are reported of patients with deletions of chromosome 5q. Bo th have familial adenomatous polyposis (FAP) and mild mental retardati on. In both, macroscopic polyposis was confined to the proximal colon in adult life (in their thirties) although microscopic adenomatosis wa s shown in the more distal colon with occasional single polyps. Both s ubjects had dermoid cysts, and congenital hypertrophy of the retinal p igment epithelium (CHRPE) was seen in case 2. Case 1 has gastroduodena l polyps and desmoid tumours; case 2 has a marfanoid habitus with an a bnormal pectus, wasted calf muscles and clawing of the toes, and Carol i's syndrome. His deletion is cytogenetically more extensive than that in case 1. The paucity of adenomas in the left side of the colon sugg ests that FAP cannot always confidently be excluded by sigmoidoscopy a lone. The expression of the disease in the colon in these cases could be milder than in the more usual autosomal dominant cases where nonsen se mutations resulting from single base changes of small deletions rat her than deletion of the whole gene are the usual finding.