GENETICS MCQs

GENETICS MCQs

1- A four-year-old boy came to your clinic with a history of seizures and

developmental delay. When you examined him you found that he was short

and has huge liver. The most likely diagnosis among the following conditions

is:

a. Pompe disease

b. Glycogen storage disease type I

c. Tyrosinemia type II

d. Phenylketonuria

e. Morquio syndrome

2- The parents of a 3-year-old boy were very concerned about their child's

cognitive ability. They also reported that he had abnormal behavior. However,

the child has never been admitted to the hospital. You sent a blood sample for

tandem mass spectrometry and the result was abnormal. Which of the

following therapeutic intervention is the best approach:

a. Dietary restriction

b. L-carnitine

c. Vitamin B12 injection

d. Enzyme replacement therapy

e. Sodium benzoate

3- The nursery called you to examine a newborn baby because of Down

syndrome features. Which of the following statements is true about this

syndrome?

a. Aneuploidy is the most common chromosomal finding

b. Nondisjunction occurs during mitosis in most cases

c. The meiotic error occurs in paternal gametes

d. Maternal serum testing is not a good prenatal screening method for

Down syndrome

e. Translocation Down syndrome is a milder form

4- Which one of the following diseases is included in the Saudi National

Newborn Screening Program:

a. Nonketotic hyperglycinemia

b. Zellweger syndrome

c. Biotinidase deficiency

d. Tyrosinemia

e. Very long chain acyl CoA dehydrogenase deficiency (VLCAD)

5- A two-year-old girl was referred to you for evaluation of wide wrests. She was

also noticed to have hepatomegaly. Her routine investigations revealed that

she had metabolic acidosis. The diagnostic testing for this condition is:

a. Urine analysis

b. Blood tandem MS

c. Bone profile

d. X-ray wrest

e. Blood gases

6- You have evaluated a 10-year-old boy with learning disability. The mother

told you that her sister had learning problems too. When you reviewed the

chart, you found an abnormal result of a triplet repeat expansion test. The most

likely diagnosis is:

a. Sotos syndrome

b. Fargile X syndrome

c. Beckwith-Wiedemann syndrome

d. Simpson-Golabi syndrome

e. Seckel syndrome

7- You were covering the NICU when you received a call from the emergency

room physician telling you that he had just intubated a 10 day old neonate who

came in coma. When you got inside the room you were struck by a very

unusual smell. His mother told you that he was well until three days ago. She

also mentioned that she had a girl who died at one month of age of unknown

cause. After examining the baby, you quickly reviewed his CBC, blood gases,

and ammonia and all were normal. The best course of action is :

a. Wait for tandem MS result

b. Start antibiotic and observe for any improvement

c. Send urine sample for urgent organic acid analysis

d. Immediate dialysis

e. CSF analysis for glycine.

8- At a given locus, both parents have (Aa) genotype for a recessive trait. The

proportions of the genotypes in their children will be:

a. 1 AA: 2 Aa: 1 aa

b. 2 AA: 1 Aa: 1 aa

c. 1 AA: 1 Aa: 2 aa

d. 1 AA: 1 Aa: 1 aa

e. 2 AA: 2 Aa : 2 aa

9- A psychiatrist referred a 12-year-old boy to your clinic. You found that he had

been seen by ophthalmology too. On examination, you noticed that he was tall

and thin and had scoliosis. Which one of the following is a true statement

about this disorder?

a. Urine organic acid analysis is the best diagnostic approach

b. Tandem MS will show highly elevated amino acid

c. Some patients are vitamin B1 responsive

d. The inheritance pattern is mitochondrial

e. The disorder is included in the Saudi National Newborn Screening

Program

10- The National Laboratory for Newborn Screening notified you that your one

week patient has abnormal tandem MS with highly elevated

propionylcarnitine. The most likely diagnosis is:

a. Fatty acid oxidation defect

b. MSUD

c. Methylmalonic acidemia

d. Homocystinuria

e. Isovaleric acidemia

11- In X-linked recessive pedigrees:

a. Male to male transmission is characteristic

b. Males and females are equally affected

c. For an affected male, all his sons will be normal and all his daughters

will be affected

d. For a carrier mother, 25% of her sons will be normal

e. Heterozygous females may express the disease because of skewing X

inactivation

12- The mother of a 2-day-old boy brought him to the emergency room because of

poor feeding and vomiting. His CBC and serum electrolytes were normal.

Ammonia was 430 uM. What is the most appropriate test that you would

request?

a. Liver function tests

b. Blood gases

c. Plasma amino acids

d. Urine succinylacetone

e. Blood carnitine level

13- You intubated a 2-day old baby because of recurrent attacks of apnea and

seizures. You suspected a metabolic disorder, however tandem MS was

unremarkable. Among the following conditions, the most likely diagnosis is:

a. Nonketotic hyperglycinemuia

b. Propionic acidemia

c. MSUD

d. Argininosucsinic acidemia

e. Methylmalonic acidemia

14- There are about 3 billion bases in human DNA. Approximately what percent

of these bases actually code for genes?

a. 100%

b. 70-80%

c. 30-50%

d. 15-20%

e. 1-2%

15- You are assessing a neonate who presented to the emergency room with severe

metabolic acidosis. Urine analysis showed massive ketosis. Which of the

following medications you need to prescribe for the patient?

a. Arginine

b. Sodium benzoate

c. Sodium phenylbutyrate

d. Vitamin B12

e. Vitamin B6

16- In a child with deafness and alopecia, the laboratory work up reveals that he

has lactic acidosis. The most likely diagnosis is :

a. Ectodermal dysplasia

b. MELAS

c. Biotinidase deficiency

d. Vitamin D resistant rickets

e. Glycogen storage disease

17- Enzyme replacement therapy is available to which of the following metabolic

disorders:

a. Niemann-Pick disease

b. Maroteaux-Lamy syndrome

c. Phenylketonuria

d. Biotinidase deficiency

e. Glycogen storage disease type I

18- The NICU nurse informed you that she was not able to insert a nasogastric

tube for one of the babies who has congenital heart disease. When you

examined him, you detected a defect in the iris. What is the pattern of

inheritance of this condition?

a. X-linked recessive

b. Autosomal recessive

c. Mitochondrial

d. Multifactorial

e. Autosoaml dominant

19- How many conditions does the Saudi National Newborn Screening Program

screen for?

a. 6

b. 10

c. 16

d. 29

e. 2

20- You examined a 15-month-old boy who had developmental delay. You

noticed hypotonia and huge liver and spleen. When you reviewed his chart,

you found that had normal tandem MS, urine organic acid analysis, and lactic

acid. However, he had a bone marrow examination which was abnormal. Of

the following, what is the most appropriate diagnostic test?

a. Liver biopsy for histochemical staining

b. Nerve conduction velocity

c. Skin biopsy for enzyme assay

d. Echocardiogram

e. Muscle biopsy

21- While you are on call for the NICU, the chemistry laboratory calls you for an

abnormal ammonia level on 5-day-old neonate who is on mechanical

ventilation. The most appropriate treatment is:

a. Peritoneal dialysis

b. IV carnitine

c. PO sodium benzoate

d. Keep NPO

e. High dextrose in the IVF

22- Which of the following statement is true?

a. Lisch nodules are one of the diagnostic criteria for neurofibromatosis II

(NF II)

b. Bilateral acoustic neuromas are distinctive features of tuberous

sclerosis

c. Unilateral nevus involves the upper half of the face in Sturge-Weber

syndrome

d. Both parents are typically affected in children with neurofibromatosis I

e. The father of a girl with incontinenta pigmenti is usually affected

23- When you examined a one-year-old girl with developmental delay, you found

severe hypotonia and optic atrophy. She also had macrocephaly. The preferred

biochemical test is:

a. Urine organic acid

b. Tandem MS

c. Plasma amino acid

d. Hexosaminidase A level

e. VLCFA level

24- An apparently healthy neonate has abnormal newborn screening. The parents

tell you that they had another infant who was perfectly well before his sudden

death. Of the following, what is the most likely diagnosis:

a. CPS deficiency

b. Propionic acidemia

c. Medium chain acyl CoA dehydrogenase (MCAD) deficiency

d. Long QT syndrome

e. Autosomal recessive cardiomyopathy

25- A newborn baby developed convulsion. When you examined her, you detected

an abdominal wall defect. Of the following, the most likely diagnosis is?

a. Trisomy 18

b. Beckwith-Wiedmann syndrome

c. Trisomy 13

d. Zellweger syndrome

e. Cri-du chat syndrome

26- A newborn baby was found to have high forehead, epicanthal folds, and

profound hypotonia. His consanguineous parents informed you that they had

an infant who died at the age of 4 months with similar problem. The

biochemical defect is likely to be found in which of the following organelles?

a. Mitochondria

b. Golgi apparatus

c. Peroxisomes

d. Ribosomes

e. Lysosomes

27- Which of the following metabolic disorder/treatment matching is appropriate?

a. Homocystinuria and vitamin B6

b. MSUD and carnitine

c. Propionic acidemia and Coenzyme Q10

d. Biotinidase deficiency and riboflavin

e. Zellweger syndrome and fat restriction

28- Nonsyndromic deafness is characterized by:

a. Locus heterogeneity

b. A defect in one gene that causes the vast majority of cases

c. Mitochondrial inheritance in most families

d. Mental retardation

e. Blindness

29- You were consulted on a child with a metabolic disorder to provide your

opinion whether he is a candidate for bone marrow transplantation. In which

of the following diseases you would consider this treatment option?

a. Sanfilippo syndrome

b. X-linked adrenoleukodystrophy

c. Morquio syndrome

d. Neonatal adrenoleukodystrophy

e. VLCAD

30- A 2 year old girl presented with hepatosplenomegaly and developmental

delay. Her eye exam revealed cherry red macula. Of the following, what is the

most likely diagnosis?

a. Hurler syndrome

b. Krabbe disease

c. Glycogen storage disease

d. Tay-Sachs disease

e. Sandhoff disease

31- The mother of a one-month-old baby was concerned about yellowish

discoloration of his eyes and skin. You suspected a metabolic disorder. You

send urine analysis which was positive for reducing substances, however,

tandem MS was normal. Which of the following statement is true?

a. Tandem MS was normal because this particular disorder is not

included in the National Newborn Screening Program

b. Enzyme assay is the diagnostic test

c. The disorder does not cause cognitive delay

d. The jaundice is likely due to unconjugated hyperbilirubinemia

e. Cataract cannot be seen in the first week of life

32- Which of the following statements about sex chromosomes anomalies is true?

a. Turner syndrome is a euploidy disorder

b. 45, X is rarely found in spontaneous abortion

c. Patients with Klinefelter syndrome are usually fertile

d. 47, XXY males are typically mentally retarded

e. 47, XYY males may have behavioral problems

33- Which of the following statements is true in cases with mitochondrial

disorders?

a. Normal lactate excludes mitochondrial defect

b. Neuromuscular manifestations are very unusual

c. Variability in clinical presentation is characteristic

d. All mitochondrial disorders have mitochondrial pattern of inheritance

e. Deafness is rarely seen in patients with mitochondrial disorders

34- Which of the following statements is true?

a. Homocystinuria causes upward lens dislocation

b. Biotinidase deficiency is an incurable disease

c. Neuronal ceroid lipofuscinosis is a common white matter

neurodegenerative disease

d. Endotracheal intubation is risky in patients with MPS

e. CSF analysis is not essential to diagnose nonketotic hyperglycinemia

35- Which of the following diseases is inherited as autosomal dominant?

a. Ataxia telangiectasia

b. MELAS

c. Hunter syndrome

d. PKU

e. Familial hypercholesterolemia

36- 12-year-old boy was evaluated by cardiology for supravalvualr aortic stenosis.

The parents report that he is at special school but has a very friendly

personality. The most likely diagnosis is :

a. Prader-Willi syndrome

b. Fragile X syndrome

c. Williams syndrome

d. Angelman syndrome

e. Down syndrome

37- One of your neighbor's children has achondroplasia. Which of the following

features is true about this disease?

a. The parents of children with achonroplasia are short in most cases.

b. Mental retardation is observed in most patients

c. Quadriparesis is a known complication

d. In an affected child, the FGFR3 mutation is inherited form one of the

parents in most cases.

e. The trunk is short while the limbs are normal.

38- Which of the following statement is true?

a. Osteogenesis imperfecta is clinically homogenous

b. Crouzon syndrome causes severe syndactyly

c. Trisomy 18 is inherited form one of the parents

d. Mosaicism describes individuals with two different cell lines derived

from two zygotes

e. Malignancy is a well-known association with Fanconi anemia

39- Which of the following syndrome/feature matching is true?

a. Cri-du-chat deletion of chromosome 4

b. Alagille syndrome posterior embryotoxin

c. Parder-Willi syndrome deletion of the maternal 15q11

d. DiGeorge syndrome hypercalcemia

e. William syndrome hypocalemia

40- Which of the following is true about multifactorial disorders?

a. Genes play no role in their causation

b. In most cases of cancer, somatic and not germline gene defect is

detected

c. The risk of recurrence for another affected child is 25%

d. Presentation in adulthood is rare

e. No sex predilection is observed.

41- The parents of a 3 year old girl came to your clinic to evaluate their daughter

because she had been loosing her developmental skills. You noticed that she

had stereotypic hand movements. Which of the following is true about this

disease?

a. Males are commonly affected

b. It is inherited as X-linked recessive

c. Children are typically affected before 6 months of age

d. A gene has been identified to cause this disease

e. An affected child commonly inherits the mutation from her