Q20. Deficiency of clotting factor IX is associated with which disorder?
(A) Haemophilia A
(B) Haemophilia B
(C) Sickle-cell anaemia
(D) Cystic fibrosis
Answer: (B) Haemophilia B
Explanation: Haemophilia B results from variants affecting clotting factor IX, whereas haemophilia A involves factor VIII. Both are usually X-linked recessive and can produce prolonged bleeding. Accurate identification of the deficient factor is important when selecting replacement or preventive treatment.
Q19. Duchenne muscular dystrophy is primarily associated with a defect in which protein?
(A) Dystrophin
(B) Keratin
(C) Collagen type II
(D) Elastin
Answer: (A) Dystrophin
Explanation: Duchenne muscular dystrophy involves variants of the DMD gene leading to absent or markedly reduced functional dystrophin. Muscle fibres become vulnerable to damage during contraction. The condition is typically X-linked recessive and frequently begins in early childhood.
Q18. Which of the following is best described as a multifactorial or polygenic disease?
(A) Classic haemophilia A
(B) Typical Down syndrome
(C) Type 2 diabetes mellitus
(D) Turner syndrome
Answer: (C) Type 2 diabetes mellitus
Explanation: Type 2 diabetes usually reflects contributions from numerous genetic variants interacting with environment and lifestyle. Unlike a typical single-gene disorder, it does not follow a simple Mendelian ratio. Insulin resistance and impaired pancreatic beta-cell function are central features.
Q17. In ordinary human mitochondrial DNA inheritance, the offspring receive mitochondrial DNA mainly from which parent?
(A) Father only
(B) Mother only
(C) Both equally
(D) Neither parent
Answer: (B) Mother only
Explanation: Human mitochondrial DNA is ordinarily passed through the egg, making mitochondrial inheritance maternal. An affected mother may pass a mitochondrial variant to sons and daughters, but an affected father does not normally transmit it. Disease severity can depend on heteroplasmy.
Q16. Which reproductive approach allows genetic testing of embryos before implantation?
[RRB Nursing Superintendent – 29 Apr 2025, Shift 1]
(A) Chorionic villus sampling
(B) Amniocentesis
(C) IVF with preimplantation genetic testing
(D) Non-invasive prenatal testing
Answer: (C) IVF with preimplantation genetic testing
Explanation: Preimplantation genetic testing, performed with IVF, assesses selected chromosomal or genetic features of embryos before uterine transfer. Amniocentesis, chorionic villus sampling and cell-free DNA screening concern pregnancies already established rather than embryos before implantation.
Q15. The National Sickle Cell Anaemia Elimination Programme announced in the Union Budget 2023 targets the elimination of genetic transmission by which year?
[SSC MTS – 12 Nov 2024, Shift 2]
(A) 2049
(B) 2045
(C) 2040
(D) 2047
Answer: (D) 2047
Explanation: India’s national sickle-cell programme set a 2047 elimination goal, marking the centenary of independence. The strategy emphasises population screening, counselling and linkage to care in affected regions. Sickle-cell disease results from inherited variants in the beta-globin gene.
Q14. Which inherited blood disorder affects haemoglobin synthesis and causes ineffective erythropoiesis?
[SSC CHSL Tier-I – 14 Aug 2023, Shift 2]
(A) Somatostatinoma
(B) Thalassaemia
(C) Venous thromboembolism
(D) Polycythaemia vera
Answer: (B) Thalassaemia
Explanation: Thalassaemia comprises inherited disorders with reduced production of alpha- or beta-globin chains. Imbalanced globin synthesis damages developing red blood cells and can cause chronic anaemia. Severe forms may require transfusions and careful prevention of iron overload.
Q13. Which of the following is NOT an inherited genetic disorder?
[SSC CGL Tier-II – 27 Oct 2023]
(A) Down syndrome
(B) Cystic fibrosis
(C) Malaria
(D) Muscular dystrophy
Answer: (C) Malaria
Explanation: Malaria is an infectious illness caused by Plasmodium parasites and spread primarily by infected Anopheles mosquitoes. The other choices are genetic conditions, though Down syndrome commonly arises through a new nondisjunction event rather than conventional family inheritance.
Q12. Down syndrome, which may cause developmental differences, belongs to which category?
[SSC CHSL Tier-I (2020 cycle) – 4 Aug 2021, Shift 2]
(A) Bacterial disease
(B) Genetic disorder
(C) Fungal disease
(D) Viral disease
Answer: (B) Genetic disorder
Explanation: Down syndrome is a genetic condition involving extra chromosome 21 material, most often an entire extra chromosome. This alteration affects development from conception. It is neither an infectious disease nor a deficiency disease, although clinical manifestations vary considerably.
Q11. Down syndrome is also known by which chromosomal description?
[RRB Staff Nurse – 21 Jul 2019, Shift 1]
(A) Trisomy 13
(B) Trisomy 18
(C) Trisomy 21
(D) Monosomy 13
Answer: (C) Trisomy 21
Explanation: In the most common form of Down syndrome, cells contain three copies of chromosome 21. It is therefore called trisomy 21. Trisomy 13 is Patau syndrome and trisomy 18 is Edwards syndrome, both distinct chromosomal conditions.
