Need with this health case study
case:
a 6-month-old infant began to vomit occasionally and ceased to gain weight. at age 8.5 months he was readmitted to the hospital. routine examination and laboratory tests were normal, but after 1 week he became habitually drowsy, his temperature rose to 39.4ºc, his pulse was elevated, and his liver was enlarged. the electroencephalogram was grossly abnormal. since the infant could not retain milk given by gavage feeding, intravenous glucose was administered to him. he improved rapidly. urinalysis showed abnormally high amounts of glutamine and uracil. this suggested a high blood ammonium concentration, which was confirmed by the laboratory tests, and in addition, showed low blood urea nitrogen.
questions:
1) which metabolic pathway might be affected in this patient?
2) which specific enzyme may be defective in the metabolic pathway in question 1?
3) are there other known defects of enzymes in this metabolic pathway? how might their defects show up in analysis?
4) why was the urine glutamine concentration elevated?
5) offer a genetic explanation for the observation that this disease is usually lethal in male patients, but not in affected female patients?
6) this patient was treated using procedures available at the time (goldstein et al., pediatr. res. 8: 5, 1974). he was given a daily diet of 1.5 g of protein/kg body weight. after 2 years on this diet, his height and weight were judged to be normal for his age. what is the effect of diet on a growing child in terms of nitrogen balance?
7) how would the treatment of a similar patient differ with today’s technology (what are some newer treatment strategies for this metabolic defect)?
references:
batshaw ml et al. 1982. treatment of inborn errors of urea synthesis: activation of alternative pathways of waste nitrogen synthesis and excretion. n engl j med 306: 1387.
brusilow and horwich. 1995. urea cycle enzymes. in scriver cr et al., editors: the metabolic and molecular bases of inherited disease. edition 7, new york, mcgraw-hill