Question

Question 16: Mention any two autosomal genetic disorders with their symptoms.

Class 12 - Biology - Principles of Inheritance and Variation Page 94

Answer 1

phenyl ketonuria: due to deficiency of phenyl alanine hydroxylase, phenylalanine increase in blood and this phenyl alanine accumulates in brain and destroy brain cell. so it causes memtal retardation.
albinism: deficiency of enzyme tyrosinase there fore the body parts like skin , iris of eye etc become melanin deficient.

Answer 2

Answer:

Two autosomal genetic disorders are as follows.

1. Sickle cell Anaemia

It is an autosomal linked recessive disorder, which is caused by point mutation in the beta-globin chain of haemoglobin pigment of the blood. The disease is characterized by sickle shaped red blood cells, which are formed due to the mutant haemoglobin molecule. The disease is controlled by HbA and HbS allele. The homozygous individuals with genotype, HbS HbS, show the symptoms of this disease while the heterozygous individuals with genotype, HbA HbS, are not affected. However, they act as carriers of the disease.

Symptoms

Rapid heart rate, breathlessness, delayed growth and puberty, jaundice, weakness, fever, excessive thirst, chest pain, and decreased fertility are the major symptoms of sickle cell anaemia disease.

(b) Down’s syndrome

It is an autosomal disorder that is caused by the trisomy of chromosome.

Symptoms

The individual is short statured with round head, open mouth, protruding tongue, short neck, slanting eyes, and broad short hands. The individual also shows retarded mental and physical growth.

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