Reduced serum levels of vitamin A and E even in the normal range are associated with an increased rate of pulmonary exacerbations in CF. Further studies are required to confirm the necessity of supplementation of vitamins A and E to PS patients.

In CF-PS, poor correlation was found between IRT, fecal elastase-1, and CFA, therefore neither fecal elastase-1 in the stool nor IRT in the serum reaches the sensitivity or the specificity of the fecal fat excretion. Thus, fecal fat excretion is required in patients with CF for evaluation of pancreatic function.

In view of the technical difficulties inherent in using stool fat estimations as a parameter of malabsorption, we used a fatty meal absorption test. Children under investigation for failure to thrive were divided into two groups, those having a normal stool fat output (less than 3.2 g/day) constituting the control group, and those having steatorrhea. After a fatty meal containing 25 g of margarine and 25 g of butter fat, we measured the rise of serum triglycerides and chylomicrons hourly for 5 h. Serum triglyceride rise of less than 100 mg/dl or less than 100% above basal values and the appearance of less than 7% of chylomicrons were considered pathological. Of our control group 95% had a normal rise of triglycerides; and 96% of our patients with steatorrhea had an abnormal rise. This test was more reliable than the two-point triglyceride test previously described for the diagnosis of fat malabsorption. The fatty meal test as described here is considered to be a useful test of absorptive function.

Two brothers of Arab origin, aged 15 and 10 years, with isolated congenital lipase and colipase deficiency are described. Both were normally developed with a history of passing greasy stools since early infancy. Both have remarkable steatorrhoea and low serum carotene and vitamin E concentrations. After exocrine pancreatic stimulation, lipase and colipase activities in the duodenal fluid were almost completely absent, while amylase trypsin, bile salt, and pH values were normal. No other aetiology for exocrine pancreatic insufficiency was found. This is the first report of congenital combined lipase and colipase deficiency in two brothers.Congenital isolated pancreatic enzyme deficiencies are rare causes of malabsorption in infancy and childhood.' The only occurrence of isolated colipase deficiency in two brothers was reported by Hilderbrand et al,2 while only one case of isolated combined congenital lipase-colipase deficiency was published by Fayez et al. ' To the best of our knowledge, the present report is the first to document isolated lipase-colipase deficiency in two brothers.