CBSE EXAM QUESTIONS WITH CORRECT
ANSWERS 2025/2026
Alkaptonuria - CORRECT ANSWER -Absence of homogentisate oxidase
- arthritis
- discolored sclerae and other areas (ear cartilage)
- Dark urine
- spinal disc degeneration and dense calcifications possible
What is the cause of "bitter almond" breath? - CORRECT ANSWER -Cyanide poisoning
What does cyanide inhibit? - CORRECT ANSWER -Cytocrhome oxidase in the ETC
What is the treatment for cyanide poisoning? - CORRECT ANSWER -Amyl nitrate (oxidizes
hemoglobin to methemoglobin, which strongly binds cyanide)
6 month old child with frequent infections and carpopedal spasm and facial spasm upon tapping
- CORRECT ANSWER -DiGeorge Syndrome
- hypoparathyroidism and T-cell deficiency
Hypocalcemia is what causes the spasms
CATCH22 pneumonic: Chromosome 22, Abnormal facies, Thymic hypoplasia, Cleft palate, and
Hypocalcemia
,Young (27 yrs old) man with lots of atherosclerotic plaques and small, raised yellow-brown
lesions on extensor surfaces of arms - CORRECT ANSWER -Familial hypercholesterolemia (FH)
Inherited disorder that causes high serum cholesterol levels
the lesions are xanthomas caused by deposits of the cholesterol
A baby is born with severe abnormalities, including prominent epicanthal folds, up slanting
palpebral fissures, and macroglossia. He also has thick skin at the nape of the neck
He vomits greenish material immediately after eating - CORRECT ANSWER -Down Syndrome
The vomiting is due to GI disorder which they often have
Boy is born with flat feet, long face, large ears, and an abnormal appearing X-chromosome -
CORRECT ANSWER -Fragile X syndrome
Expansion of a CGC trinucleotide repeat sequence on the X chromosome
X-linked genetic
The most common cause of mental retardation is - CORRECT ANSWER -Fragile X syndrome
A baby begins to get sick after weaning from breast milk, and has a low glucose level which is
not lost in urine - CORRECT ANSWER -Fructose intolerance
Fructose-1-phosphate levels will be elevated in liver cells
, A 12 year old intellectually disabled boy presents with vision difficulties. Exam reveals bilateral
dislocated lenses and a tall, thin body habitus. Labs show increased levels of serum methionine
and serum homocysteine - CORRECT ANSWER -Homocysteinuria caused by cystathionine
synthase
Also at risk for CV disease and osteoporosis
HOMOCY
Homocyteine in urine, osteoporosis, marfoid habitus, ocular changes, kYphosis
Can also be intellectually disabled
1 year old presents with abnormalities. PE reveals developmental delay, coarse facial features,
skeletal abnormalities, umbilical hernia, corneal clouding. Baby's liver and spleen are enlarged,
and the joints are stiff - CORRECT ANSWER -Hurler Syndrome
One of the mucopolysaccharidoses diseases
Caused by alpha L-iduronidase defect (can't break down dermatin sulfate and heparan sulfate -
accumulates in tissues)
Hunter's Syndrome vs Hurler's Syndrome - CORRECT ANSWER -Hunters = mild Hurler's +
aggressive behavior, no corneal clouding
2 year old with mental retardation and restricted joint movement. PE reveals coarse facial
features and clouded corneas. Blood tests reveal elevated lysosomal enzymes in the serum.
Parents are first cousins - CORRECT ANSWER -I-cell disease
ANSWERS 2025/2026
Alkaptonuria - CORRECT ANSWER -Absence of homogentisate oxidase
- arthritis
- discolored sclerae and other areas (ear cartilage)
- Dark urine
- spinal disc degeneration and dense calcifications possible
What is the cause of "bitter almond" breath? - CORRECT ANSWER -Cyanide poisoning
What does cyanide inhibit? - CORRECT ANSWER -Cytocrhome oxidase in the ETC
What is the treatment for cyanide poisoning? - CORRECT ANSWER -Amyl nitrate (oxidizes
hemoglobin to methemoglobin, which strongly binds cyanide)
6 month old child with frequent infections and carpopedal spasm and facial spasm upon tapping
- CORRECT ANSWER -DiGeorge Syndrome
- hypoparathyroidism and T-cell deficiency
Hypocalcemia is what causes the spasms
CATCH22 pneumonic: Chromosome 22, Abnormal facies, Thymic hypoplasia, Cleft palate, and
Hypocalcemia
,Young (27 yrs old) man with lots of atherosclerotic plaques and small, raised yellow-brown
lesions on extensor surfaces of arms - CORRECT ANSWER -Familial hypercholesterolemia (FH)
Inherited disorder that causes high serum cholesterol levels
the lesions are xanthomas caused by deposits of the cholesterol
A baby is born with severe abnormalities, including prominent epicanthal folds, up slanting
palpebral fissures, and macroglossia. He also has thick skin at the nape of the neck
He vomits greenish material immediately after eating - CORRECT ANSWER -Down Syndrome
The vomiting is due to GI disorder which they often have
Boy is born with flat feet, long face, large ears, and an abnormal appearing X-chromosome -
CORRECT ANSWER -Fragile X syndrome
Expansion of a CGC trinucleotide repeat sequence on the X chromosome
X-linked genetic
The most common cause of mental retardation is - CORRECT ANSWER -Fragile X syndrome
A baby begins to get sick after weaning from breast milk, and has a low glucose level which is
not lost in urine - CORRECT ANSWER -Fructose intolerance
Fructose-1-phosphate levels will be elevated in liver cells
, A 12 year old intellectually disabled boy presents with vision difficulties. Exam reveals bilateral
dislocated lenses and a tall, thin body habitus. Labs show increased levels of serum methionine
and serum homocysteine - CORRECT ANSWER -Homocysteinuria caused by cystathionine
synthase
Also at risk for CV disease and osteoporosis
HOMOCY
Homocyteine in urine, osteoporosis, marfoid habitus, ocular changes, kYphosis
Can also be intellectually disabled
1 year old presents with abnormalities. PE reveals developmental delay, coarse facial features,
skeletal abnormalities, umbilical hernia, corneal clouding. Baby's liver and spleen are enlarged,
and the joints are stiff - CORRECT ANSWER -Hurler Syndrome
One of the mucopolysaccharidoses diseases
Caused by alpha L-iduronidase defect (can't break down dermatin sulfate and heparan sulfate -
accumulates in tissues)
Hunter's Syndrome vs Hurler's Syndrome - CORRECT ANSWER -Hunters = mild Hurler's +
aggressive behavior, no corneal clouding
2 year old with mental retardation and restricted joint movement. PE reveals coarse facial
features and clouded corneas. Blood tests reveal elevated lysosomal enzymes in the serum.
Parents are first cousins - CORRECT ANSWER -I-cell disease
