Advertisements
Advertisements
प्रश्न
Why is thalassemia cotegorised as a Mendelian disorder? Write the symptoms and explain the causes of the disease. How does it differ from Sickle cell anaemia?
Advertisements
उत्तर
- Mendelian disorders are caused by changes or mutations in a gene. Thalassemia is caused by a gene deletion or mutation that codes for the alpha (a) or beta (P) globin chains of the haemoglobin molecule. Hence Thalassemia is a hereditary condition.
- It is a quantitative problem of synthesising a small number of globin molecules.The alpha chain is controlled by two genes on chromosome 16, HBAl and HBA2, while the β chain is controlled by a single gene on chromosome 11, HBB.
- A deletion or mutation in any of these genes reduces the production of the corresponding globin chains. Thalassemia symptoms include anaemia, pale yellow complexion, changes in the size and shape of RB Cs, sluggish growth and development, dark urine, and so on.
- Massive blood transfusion is needed for these patients.
- Thalassemia varies from sickle cell anaemia in the following ways: Thalassemia is a quantitative problem caused by the inability to synthesise a sufficient number of globin molecules, whereas sickle cell anaemia is a qualitative problem caused by the inability to synthesise an improperly functioning globin.
APPEARS IN
संबंधित प्रश्न
Mention any two autosomal genetic disorders with their symptoms.
Attempt any TWO of the following:
‘The gene for sickle cell anaemia in homozygous condition is lethal and produces sickle cell trait in heterozygous carrier’. Explain.
Write a note on Down’s syndrome.
Read the following statements and select the correct option.
i. Genetic disorders are broadly categorised as, Mendelian disorders and chromosomal disorders.
ii. Mendelian disorders are caused due to absence or excess of one or more chromosomes or their abnormal arrangement.
iii. Chromosomal disorders are mainly caused due to alteration or mutation in the gene.
Choose the correct option which appropriately classifies the following disorders into Mendelian and chromosomal disorders:
Colour blindness, Down syndrome, Sickle cell anaemia, Turner syndrome, Thalassemia, Haemophilia, Phenylketonuria, Klinefelter syndrome.
Select the disease which is caused by recessive autosomal genes when present in homozygous conditions.
The technique exployed in human genetic counselling is:
If a father and son are both defective in red-green colour vision, is it likely that the son inherited the trait from his father? Comment.
Identify chromosomal disorder caused due to non-disjunction of the 21st number of chromosomes and enlist its symptoms.
Jacob is genetically a carrier of the disorder that affects the shape of the RBCs, as shown in the diagram below. His son James suffers from the same disorder.
- Give the biochemical reason for the disorder that changes the shape of the RBCs, as shown above.
- Draw a Punnett square to show the genotype of the mother of James.
- Name and define the type of 'point mutation' responsible for this disorder.
