16. Mention any two autosomal genetic disorders with their symptoms.
The two autosomal genetic disorders are as follows
1. Sickle cell anaemia – It is an autosome linked recessive trait in which mutant haemoglobin molecules undergo polymerization under low oxygen tension causing a change in the shape of the RBC from biconvex disc to elongated sickle like structure. The defect is caused by the substitution of Glutamic acid (Glu) by Valine (Val) at the sixth position of the beta globin chain of the haemoglobin molecule. The substitution of amino acid in the globin protein results due to the single base substitution at the sixth codon of the beta-globin gene from GAG to GUG. Symptoms include rapid heart rate, breathlessness, delayed growth and puberty, weakness, fever, decreased fertility etc.
2. Down syndrome- It is an autosomal genetic disorder caused by trisomy of chromosome 21. Symptoms of Down syndrome include short stature with a round head, protruding tongue, slanting eyes, broad short hands etc.