Coexistence of cystic fibrosis and phenylketonuria.

Case Report A female infant weighing 3370 g was born by normal delivery at 39 weeks gestation to parents who believed that they were distantly related. They had one other child, a female, aged five years who was alive and well. There were no perinatal problems but an abnormal phenylalanine result from routine neonatal Guthrie card screening was confirmed by a plasma phenylalanine concentration of 934 mcmol/l on the fourteenth day (normal range 64-92 mcmol/l). Urinary phenylalanine was elevated at 45 mcmol/l (normal range 4-17 mcmol/l) and urinary phenylalanine excretion was 163 mcmol/mmol creatinine. Protein, ketoacids and phenylketones were absent from the urine. PKU was diagnosed and she was commenced on XP Analog (Scientific Hospital Supplies) together with 60 ml SMA Gold Cap (Wyeth) for 3 days increasing to 210 ml SMA Gold Cap to provide a small but essential amount of phenylalanine.