Name a blood related autosomal Mendelian disorder. Why is it called Mendelian disorder? How is the disorder tansmitted from parents to offsprings ?

Explanation

A blood related autosomal mendelian disorder is sickle cell anaemia. It is called a medelian disorder because :
(i) It is caused by mutation in the single gene viz, substitution of glutamic acid by valine in the sixth portion of the beta globin chain of haemoglobin molecule. This subsitution of amino acid is due to the single base substitution at the sixth codon of the Beta-globin gene from GAG to GUG. This causes polymerisation of mutant haemoglobin molecule under low oxygen conditions causing a change in shpae of RBCs from biconcave discs to elongated sickle cell structure.
(ii) Stickle cell anamia follwos mendelian pattern of inheritance. Sickle cell anaemia can be transmitted from parents to the offspring when both the parents are heterozygous for the gene. The disease in controlled by a single allele pair, HbA and Hbs. Only homogygous individual `(Hb^(a) Hb^(s))` show disease phenotype. Heterozygous individuals though appear unaffected are carriers of disease `(Hb^(A) Hbs)` and there is 50 percent change of transmission of the mutant gene to the progeny, thus, heterozygous individuals carry Sickle cell trait.