Q.1 Which of the following is a common presentation of phenylketonuria (PKU) in infants?
Recurrent vomiting
Seizures and developmental delay
Severe diarrhea
Frequent infections
Explanation - PKU leads to accumulation of phenylalanine, causing neurotoxicity that presents as seizures, intellectual disability, and developmental delay if untreated.
Correct answer is: Seizures and developmental delay
Q.2 Maple syrup urine disease is named after which characteristic feature?
Sweet odor of urine
Dark-colored urine
Bubbly urine
Greenish urine
Explanation - Maple syrup urine disease is named because the urine of affected individuals smells like maple syrup due to branched-chain amino acid accumulation.
Correct answer is: Sweet odor of urine
Q.3 Which enzyme deficiency causes galactosemia?
Galactokinase
Galactose-1-phosphate uridyltransferase
Aldolase B
Hexokinase
Explanation - Classic galactosemia is caused by deficiency of galactose-1-phosphate uridyltransferase, leading to failure to metabolize galactose properly.
Correct answer is: Galactose-1-phosphate uridyltransferase
Q.4 In Tay-Sachs disease, which enzyme is deficient?
Hexosaminidase A
Glucocerebrosidase
Arylsulfatase A
Sphingomyelinase
Explanation - Tay-Sachs disease results from deficiency of Hexosaminidase A, leading to GM2 ganglioside accumulation in neurons.
Correct answer is: Hexosaminidase A
Q.5 A child with recurrent vomiting, lethargy, and hyperammonemia is likely suffering from?
Urea cycle disorder
Diabetes insipidus
Phenylketonuria
Cystic fibrosis
Explanation - Urea cycle disorders result in impaired nitrogen elimination, causing hyperammonemia, vomiting, and encephalopathy.
Correct answer is: Urea cycle disorder
Q.6 Which dietary modification is essential in managing phenylketonuria?
Low lactose diet
Low protein diet with phenylalanine restriction
High fat diet
Low salt diet
Explanation - Patients with PKU require a low protein diet with phenylalanine restriction to prevent neurotoxicity while maintaining essential nutrition.
Correct answer is: Low protein diet with phenylalanine restriction
Q.7 What is the inheritance pattern of most inborn errors of metabolism?
Autosomal dominant
Autosomal recessive
X-linked dominant
Mitochondrial
Explanation - Most inborn errors of metabolism follow an autosomal recessive inheritance pattern, meaning both parents must pass on the defective gene.
Correct answer is: Autosomal recessive
Q.8 Which feature is NOT typical of Gaucher disease?
Hepatosplenomegaly
Bone pain
Cherry-red spot in macula
Anemia
Explanation - Cherry-red spot is a feature of Tay-Sachs disease, not Gaucher disease, which presents with hepatosplenomegaly, anemia, and bone pain.
Correct answer is: Cherry-red spot in macula
Q.9 Newborn screening for PKU commonly uses which test?
Guthrie bacterial inhibition assay
ELISA for phenylalanine
PCR for mutation
Urinary ketone test
Explanation - The Guthrie bacterial inhibition assay is a standard screening test for PKU, detecting elevated phenylalanine levels.
Correct answer is: Guthrie bacterial inhibition assay
Q.10 Which of the following is a feature of homocystinuria?
Tall stature with lens dislocation
Short stature with deafness
Hepatosplenomegaly
Microcephaly
Explanation - Homocystinuria presents with Marfanoid features like tall stature, lens dislocation, intellectual disability, and vascular complications.
Correct answer is: Tall stature with lens dislocation
Q.11 Which metabolic disorder responds to vitamin B6 supplementation?
Homocystinuria
Maple syrup urine disease
Phenylketonuria
Galactosemia
Explanation - Some cases of homocystinuria due to cystathionine beta-synthase deficiency respond to high-dose vitamin B6 supplementation.
Correct answer is: Homocystinuria
Q.12 Which organ is primarily affected in glycogen storage disease type I (von Gierke’s disease)?
Heart
Brain
Liver
Muscles
Explanation - Von Gierke’s disease is due to glucose-6-phosphatase deficiency, leading to hepatomegaly and hypoglycemia.
Correct answer is: Liver
Q.13 Which metabolic disorder is commonly associated with cherry-red spot in macula?
Tay-Sachs disease
Gaucher disease
Pompe disease
Hurler syndrome
Explanation - A cherry-red spot in the macula is a classical finding in Tay-Sachs disease due to GM2 ganglioside accumulation.
Correct answer is: Tay-Sachs disease
Q.14 Which metabolic disorder is treated with avoidance of fasting and frequent carbohydrate meals?
Galactosemia
Von Gierke’s disease
Maple syrup urine disease
Phenylketonuria
Explanation - Von Gierke’s disease is managed by avoiding fasting and providing frequent carbohydrate intake to prevent hypoglycemia.
Correct answer is: Von Gierke’s disease
Q.15 Hurler syndrome is caused by deficiency of which enzyme?
Iduronidase
Glucocerebrosidase
Sphingomyelinase
Arylsulfatase A
Explanation - Hurler syndrome (MPS I) results from alpha-L-iduronidase deficiency, leading to accumulation of dermatan and heparan sulfate.
Correct answer is: Iduronidase
Q.16 Which amino acid becomes essential in phenylketonuria?
Tyrosine
Lysine
Valine
Methionine
Explanation - In PKU, phenylalanine cannot be converted to tyrosine, making tyrosine an essential amino acid that must be supplemented.
Correct answer is: Tyrosine
Q.17 Pompe disease primarily affects which organ system?
Nervous system
Respiratory system
Cardiac and muscular system
Digestive system
Explanation - Pompe disease is a glycogen storage disorder that primarily causes cardiomyopathy and muscle weakness.
Correct answer is: Cardiac and muscular system
Q.18 Which inborn error of metabolism leads to albinism?
Phenylketonuria
Tyrosinase deficiency
Alkaptonuria
Homocystinuria
Explanation - Albinism is due to tyrosinase deficiency, preventing melanin synthesis from tyrosine.
Correct answer is: Tyrosinase deficiency
Q.19 Which urine finding is typical in alkaptonuria?
Sweet odor
Darkening on standing
Frothy appearance
Red coloration
Explanation - In alkaptonuria, homogentisic acid accumulates and urine darkens on standing due to oxidation.
Correct answer is: Darkening on standing
Q.20 Which dietary restriction is required in galactosemia?
Lactose-free diet
Low protein diet
High carbohydrate diet
Salt-free diet
Explanation - In galactosemia, lactose-containing foods must be avoided since they provide galactose, which cannot be metabolized.
Correct answer is: Lactose-free diet
Q.21 Which metabolic disorder is diagnosed by detecting reducing substances in urine?
Galactosemia
Maple syrup urine disease
Tay-Sachs disease
Phenylketonuria
Explanation - Reducing substances in urine suggest galactosemia due to inability to metabolize galactose.
Correct answer is: Galactosemia
Q.22 Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency commonly presents with?
Hypoketotic hypoglycemia
Hypertension
Hyperglycemia
Hypocalcemia
Explanation - MCAD deficiency prevents beta-oxidation of fatty acids, leading to hypoketotic hypoglycemia during fasting.
Correct answer is: Hypoketotic hypoglycemia
Q.23 Which storage disorder is associated with foam cells and hepatosplenomegaly?
Niemann-Pick disease
Tay-Sachs disease
Homocystinuria
Phenylketonuria
Explanation - Niemann-Pick disease due to sphingomyelinase deficiency causes lipid-laden foam cells and hepatosplenomegaly.
Correct answer is: Niemann-Pick disease
Q.24 Which test is commonly used to detect homocystinuria?
Cyanide nitroprusside test
Benedict’s test
Coombs test
Sudan black staining
Explanation - Homocystinuria can be detected using cyanide nitroprusside test, which detects excess homocysteine in urine.
Correct answer is: Cyanide nitroprusside test
Q.25 Which disorder is treated with liver transplantation in severe cases?
Galactosemia
Maple syrup urine disease
Phenylketonuria
Homocystinuria
Explanation - Severe forms of maple syrup urine disease may be treated with liver transplantation to provide the missing enzyme activity.
Correct answer is: Maple syrup urine disease