SICKLE CELL ANEMIA SEX LINKED?

SICKLE CELL ANEMIA GENETICS .-Sickle cell anemia is a genetic disease that affects hemoglobin. A single nucleotide change in the hemoglobin gene causes an amino acid substitution in the normal hemoglobin (HbA) protein from glutamic acid to valine at chromosome 11. The resulting cells therefore posess abnormal hemoglobin (HbS) and are morphologically sickled in shape.

IS SICKLE CELL ANEMIA SEX LINKED?

Sickle cell anemia is an autosomal recessive disease, therefore is not sex linked. Any gender can be sickle cell diseased or carriers.

SO HOW DOES ONE GET SICKLE CELL?

If one to be a carrier, he/she has to inherit one gene for the sickle cell( HbS) and have a normal HbA to form HbAS. If one is a SC diseased, then he/she inherits defective gene from each parent to form HbSS.This is a simple explanation, based on probability,

1. A Sickle father + Sickle mother = 50% sickle daughters + 50% sickled sons.

2. A Sickled father + Carier/trait mother= 25% sickled daughters+ 25% sickled sons + 25% Carrier daughter + 25% carrier son.

3. Normal father + Sickled mother= 50% carrier daughters + 50% carrier sons.

4. Sickled father + Normal mother= 50% carrier daughters + 50% carrier sons

5. Normal fafher + normal mother= 100% normal kids.

LAB TEST and EXAMINATION

1. Blood Count A full haemogram report -depending on calibration of machine- will show a raised reticulocyte count , Low Hb

,2. Blood filmAdrop of blood treated with a drop of 2% sodium metabisulphite, waxed and incubated shows sickled erythrocytes

.3. Hb electrophoresis or a sickle solubility test will be positive. Its efficiency is much better than Metabisulphite one.