Q.1 Which genetic disorder is characterized by an extra copy of chromosome 21?
Turner syndrome
Down syndrome
Klinefelter syndrome
Cri-du-chat syndrome
Explanation - Down syndrome occurs due to trisomy 21, where there is an extra copy of chromosome 21.
Correct answer is: Down syndrome
Q.2 What is the inheritance pattern of cystic fibrosis?
Autosomal dominant
Autosomal recessive
X-linked dominant
Mitochondrial
Explanation - Cystic fibrosis is inherited in an autosomal recessive pattern, requiring two defective alleles.
Correct answer is: Autosomal recessive
Q.3 Which of the following is a microdeletion syndrome?
Down syndrome
Turner syndrome
DiGeorge syndrome
Klinefelter syndrome
Explanation - DiGeorge syndrome is caused by a 22q11.2 microdeletion.
Correct answer is: DiGeorge syndrome
Q.4 Which feature is most characteristic of Turner syndrome?
Tall stature
Webbed neck
Macroorchidism
Polydactyly
Explanation - Turner syndrome patients often present with short stature, webbed neck, and streak ovaries.
Correct answer is: Webbed neck
Q.5 What is the most common genetic cause of intellectual disability?
Down syndrome
Fragile X syndrome
Prader-Willi syndrome
Angelman syndrome
Explanation - Down syndrome is the leading genetic cause of intellectual disability worldwide.
Correct answer is: Down syndrome
Q.6 Fragile X syndrome is associated with which type of genetic mutation?
Point mutation
Chromosomal translocation
Trinucleotide repeat expansion
Deletion
Explanation - Fragile X syndrome is due to CGG trinucleotide repeat expansion in the FMR1 gene.
Correct answer is: Trinucleotide repeat expansion
Q.7 Which gene is affected in Duchenne muscular dystrophy?
FBN1
DMD
CFTR
HBB
Explanation - Duchenne muscular dystrophy is caused by mutations in the DMD gene encoding dystrophin.
Correct answer is: DMD
Q.8 What is the chromosomal abnormality in Klinefelter syndrome?
47,XXY
45,X
47,XXX
Trisomy 18
Explanation - Klinefelter syndrome results from an extra X chromosome in males, giving a 47,XXY karyotype.
Correct answer is: 47,XXY
Q.9 Which syndrome is associated with obesity, hypotonia, and hypogonadism?
Prader-Willi syndrome
Angelman syndrome
Marfan syndrome
Turner syndrome
Explanation - Prader-Willi syndrome is caused by loss of paternal genes on chromosome 15q11-q13.
Correct answer is: Prader-Willi syndrome
Q.10 Which inheritance pattern is typical for hemophilia A?
Autosomal recessive
Autosomal dominant
X-linked recessive
Mitochondrial
Explanation - Hemophilia A is X-linked recessive, primarily affecting males.
Correct answer is: X-linked recessive
Q.11 Which chromosome abnormality causes Edwards syndrome?
Trisomy 13
Trisomy 18
Trisomy 21
Monosomy X
Explanation - Edwards syndrome is caused by trisomy 18, associated with severe developmental delay.
Correct answer is: Trisomy 18
Q.12 Cri-du-chat syndrome is due to deletion on which chromosome?
Chromosome 5
Chromosome 7
Chromosome 11
Chromosome 15
Explanation - Cri-du-chat syndrome is caused by deletion of the short arm of chromosome 5 (5p).
Correct answer is: Chromosome 5
Q.13 Which syndrome is associated with a 'happy puppet' phenotype?
Prader-Willi syndrome
Angelman syndrome
Turner syndrome
Fragile X syndrome
Explanation - Angelman syndrome, due to loss of maternal chromosome 15q11-q13, causes developmental delay and a happy demeanor.
Correct answer is: Angelman syndrome
Q.14 Which gene mutation causes Marfan syndrome?
FBN1
COL1A1
DMD
CFTR
Explanation - Marfan syndrome is caused by mutations in FBN1, affecting fibrillin-1.
Correct answer is: FBN1
Q.15 Which metabolic disorder results from deficiency of phenylalanine hydroxylase?
Maple syrup urine disease
Alkaptonuria
Phenylketonuria
Galactosemia
Explanation - Phenylketonuria (PKU) results from deficiency of phenylalanine hydroxylase, leading to intellectual disability if untreated.
Correct answer is: Phenylketonuria
Q.16 What is the karyotype of Turner syndrome?
45,X
47,XXY
47,XXX
46,XY
Explanation - Turner syndrome is due to monosomy X (45,X).
Correct answer is: 45,X
Q.17 Which condition is due to trisomy 13?
Patau syndrome
Edwards syndrome
Down syndrome
Turner syndrome
Explanation - Patau syndrome is caused by trisomy 13 and is associated with severe congenital anomalies.
Correct answer is: Patau syndrome
Q.18 Which genetic condition is associated with tall stature and gynecomastia in males?
Turner syndrome
Klinefelter syndrome
Marfan syndrome
Noonan syndrome
Explanation - Klinefelter syndrome (47,XXY) presents with tall stature, gynecomastia, and small testes.
Correct answer is: Klinefelter syndrome
Q.19 In mitochondrial inheritance, traits are passed from which parent?
Only father
Only mother
Both equally
Neither parent
Explanation - Mitochondrial DNA is maternally inherited, so conditions are passed only from the mother.
Correct answer is: Only mother
Q.20 Which gene defect causes cystic fibrosis?
CFTR
FBN1
HBB
DMD
Explanation - Cystic fibrosis is caused by mutations in the CFTR gene affecting chloride channels.
Correct answer is: CFTR
Q.21 What is the characteristic cry of Cri-du-chat syndrome?
High-pitched, cat-like
Hoarse, low-pitched
Silent
Whisper-like
Explanation - Cri-du-chat means 'cry of the cat,' referring to the distinctive high-pitched cry in affected infants.
Correct answer is: High-pitched, cat-like
Q.22 Which condition is caused by a defect in the HBB gene?
Sickle cell anemia
Cystic fibrosis
Marfan syndrome
Duchenne muscular dystrophy
Explanation - Mutations in the HBB gene cause sickle cell anemia due to abnormal hemoglobin S.
Correct answer is: Sickle cell anemia
Q.23 Which syndrome is associated with 'elfin facies' and supravalvular aortic stenosis?
Williams syndrome
DiGeorge syndrome
Noonan syndrome
Turner syndrome
Explanation - Williams syndrome is due to 7q11.23 microdeletion, characterized by elfin facies and cardiovascular anomalies.
Correct answer is: Williams syndrome
Q.24 Which genetic disorder is diagnosed by sweat chloride testing?
Phenylketonuria
Cystic fibrosis
Galactosemia
Maple syrup urine disease
Explanation - Sweat chloride test is diagnostic for cystic fibrosis due to defective CFTR channels.
Correct answer is: Cystic fibrosis
Q.25 What is the mode of inheritance of Marfan syndrome?
Autosomal recessive
Autosomal dominant
X-linked recessive
Mitochondrial
Explanation - Marfan syndrome follows an autosomal dominant inheritance pattern.
Correct answer is: Autosomal dominant