Identifying Non-Metabolic Disorders
The question asks to identify the condition that is NOT an inborn error of metabolism (IEM). IEMs are genetic disorders typically caused by a mutation in a single gene that leads to a deficiency in a specific enzyme, disrupting a metabolic pathway.
Condition Analysis
- Tay-Sach's disease: This is an IEM. It's a lysosomal storage disorder caused by a deficiency in the enzyme hexosaminidase A, leading to the buildup of GM2 gangliosides.
- Maple syrup urine disease (MSUD): This is also an IEM. It involves defects in the metabolism of branched-chain amino acids due to enzyme deficiencies.
- Neural tube defects (NTDs): These are birth defects affecting the brain, spine, or spinal cord. They occur during embryonic development and are generally considered developmental malformations, not errors of specific metabolic enzyme function.
- Down's syndrome: This is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21 (trisomy 21). While it involves genetic factors, it's primarily a chromosomal abnormality, not an error of metabolism in the typical sense of IEMs.
Conclusion on Neural Tube Defects
Neural tube defects represent a failure of the neural tube to properly close during fetal development. Unlike Tay-Sach's disease and Maple syrup urine disease, which are clearly defined IEMs affecting specific metabolic pathways, NTDs are classified as structural birth defects. Down's syndrome is a chromosomal disorder.
Therefore, among the given options, Neural tube defects are not classified as an inborn error of metabolism.
Important Questions from Genetic Disorders & Public Health
- Amniocentesis is called for in all of the following circumstances EXCEPT:
- Consider the following pairs of genetic diseases that show Mendelian inheritance. Each of the following pairs represents a genetic disease and it has been matched with a type of inheritance :How many of the pairs given above are correctly matched?
1 Cystic fibrosis Autosomal recessive 2 Huntington's chorea Autosomal dominant 3 Marfan's syndrome Recessive sex-linked Consider the following statements :
Statement I:
Signs of thalassemia major usually develop after 6 months of age.
Statement II:
This is the time when haemoglobin synthesis switches from haemo-globin F to haemoglobin A.
Which one of the following is correct in respect of the above statements?
- Cystic fibrosis involves which of the following organs?
1. Lungs
2. Liver
3. Pancreas
4. Kidney
Select the correct answer using the code given below. - Which of the following statements are correct in respect of haemophilia?
1. It is hereditary bleeding disorder.
2. It has a higher incidence among Asians.
3. It affects females occasionally and mildly.
Select the correct answer using the code given below.
