Question

Select the autosomal dominant, autosomal recessive, $X$- sex linked recessive and $Y$-sex linked recessive disorders respectively.

• A. Myotonic dystrophy, SCA, Haemophilia and hyper trichosis
• B. Huntington’s chorea, PKU (phenylketonuria), colour-blindness and webbed toes
• C. Polydactyly, Thalassemia $G—6—P$ dehydrogenase deficiency and long hairs on pinna
• D. All of the above

Answer 1

Answer: (D)

I.Autosomal dominant disorders
e.g.: 1. Myotonic dystrophy
2. Huntington’s chorea (chromosome 4)
3. Phenylthiocarbamide (PTC) testing
4. Polydactyly in man.
II. Autosomal recessive disorders
e.g.:1. SCA disorder
2. PKU (Phenylketonuria)
3. Alkaptonuria
4. Albinism acter
5. Gaucher’s disease (chromosome-1)
6. Tay Sach’s disease
7. Thalassaemia
8. Cystic fibrosis (chromosome-7)
9. Galactosemia
III. Sex-linked (X) recessive disorders
e.g.: 1. Haemophilia/ Bleeder’s disease
2. Colour-blindness
3. Congenital night blindness
4. DMD (Duchenne’s muscular dystrophy)
5. G-6-P dehydrogenase deficiency
IV. Y Sex-linked disorder
e.g. :Hypertrichosis (long hairs present on pinna of ear) and webbed toes.