Errors In Metabolism

Question 1

Incidence of IEM

Answer 1

Collectively 1/4000

Question 2

Why is genetics important in diagnosing IEM

Answer 2

Repro choice, exact diagnosis, prevent invasive procedures, quicker diagnosis, specific therapies, prognosis info for patient

Question 3

What is glycogen storage disorder

Answer 3

Disorder of energy production.
2 clinically indistinguishable types, AR, inadequate conversion of glucose-6-phosphate -> glucose-> sever hypoglycaemia. Accumulate fat and glycogen in liver and kidney. Doll like face, fat cheeks, large abdomen, GR, delay puberty

Question 4

Genetics of glycogen storage disorder

Answer 4

AR, higher in A.jews. Biallelic mutations in G6PC

Question 5

What is OTC ornithine transcarbamylase deficiency

Answer 5

Most common urea cycle disorder. X linked. Any of 4 genes in urea cycle. Defects in metabolism of waste nitrogen from protein breakdown, ammonia accumulates in first few days of life.

Question 6

Phenotype of OTC

Answer 6

Male: severe neonatal onset. Liver transplant required by 6 months. LD, DD, ADHD.
Females and some males (partial) present later. Can be triggered by stress.

Question 7

Three types of IEM

Answer 7

1. Toxic accumulation of substrate due to a block. 2. Activation of alternate Pathway/product. 3. Deficiency in substrate after block occurred