Autosomal Recessive diseases

Question 1

List diseases

Answer 1

Cystic Fibrosis, Glycogen storage diseases, Sickle Cell, PKU, Wilsons, Thalassemia, albinism, ARPDK, mucopolysaccharidoses, sphingolipidoses

Question 2

Cystic Fibrosis

Answer 2

CFTR gene on chr. 7 Deletion of Phe508

Diagnosis: High sweat chloride, may have contraction alkalosis & hypokalemia 2/2 renal K/H wasting.
Complications: Pulm infections (pseudomonas), pancreatic insufficiency, meconium ileus, malabsorption (ADEK), steatorrhea, infertility in males (absent vas deferens/sperm(
Tx: N-acetylcysteine to loosen mucus plugs, treat infections

Question 3

Sickle Cell disease

Answer 3

HbS point mutation causes aa replacement in B chain (valine for glutaminc acid)
Newborns are asymptomatic
Heterozygotes have resistance to malaria, +/- hematuria
8% AA carry the HbS trait
Diagnosis: Hb electrophoresis
Complications: Aplastic Crisis (B19), Autosplenectomy (Howell-Jolly bodies), Salmonella osteo, Pain crisis (vaso-occlusive), splenic cequestration, renal papillary necrosis
Tx: Hydroxyurea (Increases HbF) & BMT if necessary