Q.1 Which of the following is an example of an autosomal dominant genetic disorder?
Cystic Fibrosis
Huntington's Disease
Duchenne Muscular Dystrophy
Phenylketonuria
Explanation - Huntington's Disease is inherited in an autosomal dominant manner, meaning only one copy of the defective gene is sufficient to cause the disorder.
Correct answer is: Huntington's Disease
Q.2 Cystic fibrosis primarily affects which organ system?
Respiratory system
Nervous system
Circulatory system
Skeletal system
Explanation - Cystic fibrosis leads to thick mucus production, causing chronic lung infections and respiratory complications.
Correct answer is: Respiratory system
Q.3 Down syndrome is caused by which chromosomal abnormality?
Trisomy 21
Monosomy X
Trisomy 18
Trisomy 13
Explanation - Down syndrome occurs due to the presence of an extra copy of chromosome 21.
Correct answer is: Trisomy 21
Q.4 Tay-Sachs disease is associated with a deficiency of which enzyme?
Hexosaminidase A
Glucocerebrosidase
Phenylalanine hydroxylase
Lactase
Explanation - Tay-Sachs disease results from a deficiency of Hexosaminidase A, leading to accumulation of GM2 ganglioside in neurons.
Correct answer is: Hexosaminidase A
Q.5 Which inheritance pattern is characteristic of Hemophilia A?
Autosomal dominant
Autosomal recessive
X-linked recessive
Mitochondrial inheritance
Explanation - Hemophilia A is caused by mutations in the factor VIII gene on the X chromosome and mainly affects males.
Correct answer is: X-linked recessive
Q.6 Marfan syndrome primarily affects which connective tissue protein?
Collagen
Fibrillin-1
Elastin
Keratin
Explanation - Marfan syndrome is due to mutations in the FBN1 gene encoding fibrillin-1, affecting connective tissue integrity.
Correct answer is: Fibrillin-1
Q.7 Sickle cell anemia is caused by a mutation in which gene?
HBB gene
CFTR gene
G6PD gene
PAH gene
Explanation - Sickle cell anemia results from a point mutation in the HBB gene, producing abnormal hemoglobin S.
Correct answer is: HBB gene
Q.8 Which of the following is a mitochondrial inheritance disorder?
Leber Hereditary Optic Neuropathy
Cystic Fibrosis
Duchenne Muscular Dystrophy
Turner Syndrome
Explanation - Mitochondrial disorders are maternally inherited; LHON is caused by mutations in mitochondrial DNA affecting optic nerves.
Correct answer is: Leber Hereditary Optic Neuropathy
Q.9 Phenylketonuria (PKU) leads to accumulation of which amino acid?
Phenylalanine
Tyrosine
Leucine
Tryptophan
Explanation - PKU is due to deficiency of phenylalanine hydroxylase, causing phenylalanine accumulation and neurotoxicity.
Correct answer is: Phenylalanine
Q.10 Which chromosomal disorder is characterized by short stature, webbed neck, and ovarian dysgenesis?
Turner Syndrome
Klinefelter Syndrome
Down Syndrome
Patau Syndrome
Explanation - Turner syndrome affects females with monosomy X (45,X) and presents with these physical features and gonadal dysgenesis.
Correct answer is: Turner Syndrome
Q.11 Which disorder results from a deletion on the short arm of chromosome 5?
Cri-du-chat syndrome
Williams syndrome
Prader-Willi syndrome
Angelman syndrome
Explanation - Cri-du-chat syndrome is caused by a deletion on 5p and is characterized by a cat-like cry in infants.
Correct answer is: Cri-du-chat syndrome
Q.12 Duchenne muscular dystrophy is caused by mutations in which gene?
Dystrophin gene
Fibrillin-1 gene
CFTR gene
HBB gene
Explanation - DMD is an X-linked recessive disorder due to mutations in the dystrophin gene leading to progressive muscle weakness.
Correct answer is: Dystrophin gene
Q.13 Which genetic disorder is associated with defects in DNA repair mechanisms leading to photosensitivity?
Xeroderma Pigmentosum
Marfan Syndrome
Huntington's Disease
PKU
Explanation - XP is caused by mutations in nucleotide excision repair genes, making patients extremely sensitive to UV light and prone to skin cancers.
Correct answer is: Xeroderma Pigmentosum
Q.14 Klinefelter syndrome results in which karyotype?
47,XXY
45,X
46,XY
47,XYY
Explanation - Klinefelter syndrome is a male genetic disorder where an extra X chromosome leads to hypogonadism and infertility.
Correct answer is: 47,XXY
Q.15 Which disorder is caused by a trinucleotide repeat expansion in the FMR1 gene?
Fragile X syndrome
Huntington's Disease
Myotonic Dystrophy
Cystic Fibrosis
Explanation - Fragile X is caused by CGG repeat expansion in FMR1, leading to intellectual disability and characteristic facial features.
Correct answer is: Fragile X syndrome
Q.16 Which metabolic disorder results from a deficiency of the enzyme glucocerebrosidase?
Gaucher disease
Tay-Sachs disease
PKU
Maple syrup urine disease
Explanation - Gaucher disease is a lysosomal storage disorder caused by glucocerebrosidase deficiency, leading to accumulation of glucocerebroside in macrophages.
Correct answer is: Gaucher disease
Q.17 Which disorder is characterized by progressive neurodegeneration and cherry-red macula in infancy?
Tay-Sachs disease
Phenylketonuria
Duchenne muscular dystrophy
Marfan Syndrome
Explanation - Tay-Sachs is a lysosomal storage disorder causing accumulation of GM2 ganglioside in neurons, with cherry-red macula as a hallmark.
Correct answer is: Tay-Sachs disease
Q.18 Which genetic disorder is associated with defective chloride channels?
Cystic Fibrosis
Duchenne Muscular Dystrophy
Hemophilia A
Sickle Cell Anemia
Explanation - CF is caused by mutations in the CFTR gene, which encodes a chloride channel affecting epithelial fluid transport.
Correct answer is: Cystic Fibrosis
Q.19 Which chromosomal disorder is caused by trisomy of chromosome 18?
Edwards Syndrome
Patau Syndrome
Down Syndrome
Turner Syndrome
Explanation - Edwards syndrome results from trisomy 18 and is characterized by severe developmental and congenital anomalies.
Correct answer is: Edwards Syndrome
Q.20 Which disorder results from abnormal accumulation of galactocerebroside?
Krabbe disease
Gaucher disease
Niemann-Pick disease
Tay-Sachs disease
Explanation - Krabbe disease is a lysosomal storage disorder caused by deficiency of galactocerebrosidase, leading to demyelination.
Correct answer is: Krabbe disease
Q.21 Which syndrome is caused by deletion of paternal 15q11-q13 region?
Prader-Willi Syndrome
Angelman Syndrome
Williams Syndrome
Cri-du-chat Syndrome
Explanation - Prader-Willi results from loss of paternally inherited genes on 15q11-q13, causing obesity, hypotonia, and intellectual disability.
Correct answer is: Prader-Willi Syndrome
Q.22 Angelman syndrome is primarily associated with:
Loss of maternal UBE3A gene
Trisomy 21
Fibrillin-1 mutation
Hexosaminidase A deficiency
Explanation - Angelman syndrome occurs due to loss or inactivation of the maternal UBE3A gene on chromosome 15, causing severe intellectual disability and ataxia.
Correct answer is: Loss of maternal UBE3A gene
Q.23 Which X-linked recessive disorder leads to red blood cell hemolysis under oxidative stress?
G6PD deficiency
Hemophilia A
Duchenne Muscular Dystrophy
Fragile X Syndrome
Explanation - G6PD deficiency impairs the pentose phosphate pathway in RBCs, leading to hemolysis when exposed to oxidative agents.
Correct answer is: G6PD deficiency
Q.24 Which disorder is caused by an expansion of CTG repeats in the DMPK gene?
Myotonic Dystrophy
Huntington's Disease
Fragile X Syndrome
Marfan Syndrome
Explanation - Myotonic dystrophy type 1 results from CTG trinucleotide repeat expansion in the DMPK gene, causing muscle weakness and myotonia.
Correct answer is: Myotonic Dystrophy