Genetic and Metabolic Disorders Practice Questions

Q: Acrodermatitis enteropathica is:-

Inherited disorder of impaired uptake of zinc from body. ***Inherited disorder of impaired uptake of zinc from body*** - **Acrodermatitis enteropathica** is an **autosomal recessive** genetic disorder characterized by a mutation in the **SLC39A4 gene**, which encodes a zinc transporter protein (ZIP4). - This mutation leads to **impaired absorption of dietary zinc** in the intestine, resulting in severe **zinc deficiency**. - Clinical features include **periorificial and acral dermatitis**, **diarrhea**, and **alopecia** that respond to zinc supplementation. *Inherited disorder of excessive excretion of zinc from body* - This statement is incorrect as Acrodermatitis enteropathica is due to **impaired uptake**, not excessive excretion of zinc. - Excessive excretion of zinc is not the mechanism responsible for the primary deficiency seen in this condition. *Inherited disorder of excessive excretion of copper from body* - This describes conditions like **Wilson's disease**, which involves copper accumulation due to impaired biliary excretion, not zinc deficiency. - Acrodermatitis enteropathica specifically relates to **zinc metabolism**, not copper. *Inherited disorder of impaired uptake of copper from body* - This describes conditions like **Menkes disease**, a rare X-linked recessive disorder characterized by a defect in copper transport and absorption, leading to copper deficiency. - Acrodermatitis enteropathica is distinctly a **zinc metabolism disorder**. *Inherited disorder of impaired excretion of zinc from body* - This would imply zinc accumulation rather than deficiency, which is not the pathophysiology of Acrodermatitis enteropathica. - The condition is characterized by **zinc deficiency due to malabsorption**, not problems with zinc excretion.

Q: An 8 year old boy complains of increasing muscle weakness. On examination, his calves are bulky and show muscle tightening. His serum creatine kinase levels are increasing with age. Which of the following is the most likely diagnosis?

Dystrophin deficiency. ***Dystrophin deficiency*** - The presentation of an 8-year-old boy with **increasing muscle weakness**, **bulky calves** (pseudohypertrophy), and **elevated creatine kinase** is highly characteristic of Duchenne muscular dystrophy, which is caused by a dystrophin deficiency. - The muscle tightening and progressive increase in **creatine kinase** over time further support this diagnosis, as muscle breakdown leads to enzyme release. - Duchenne typically presents between **3-5 years** with progressive weakness, wheelchair dependence by early teens, and very high CK levels (10-100x normal). *Becker muscular dystrophy* - While also caused by **dystrophin deficiency** (partial rather than complete), Becker muscular dystrophy has a **later onset** (usually age 10-15 years) and **milder, slower progression**. - The age of 8 years with significant symptoms and the rapid progression described are more consistent with **Duchenne** than Becker. *Congenital myopathy* - While hereditary muscle disorders, congenital myopathies typically present at birth or in early infancy with **generalized hypotonia** and **muscle weakness**, often static or slowly progressive. - They usually do not exhibit the prominent calf pseudohypertrophy seen in Duchenne muscular dystrophy. *Myelin deficiency* - Myelin deficiency disorders primarily affect the **nervous system**, leading to issues with nerve signal transmission rather than direct muscle weakness and pseudohypertrophy. - Symptoms would typically include **neurological deficits** such as sensory loss, ataxia, or spasticity. *Hereditary sensorimotor neuropathy* - These neuropathies (e.g., Charcot-Marie-Tooth disease) involve both **sensory and motor nerves**, leading to muscle weakness, atrophy, and sensory loss, often in the distal limbs. - They do not typically cause **calf pseudohypertrophy** or progressively high creatine kinase levels as seen in primary muscle diseases.

Q: Ataxia telangiectasia is associated with all of the following except:

Increased fraction of IgA immunoglobulins. ***Increased fraction of IgA immunoglobulins*** - Ataxia-telangiectasia is characterized by **decreased or absent IgA** and **low IgG2 and IgE** levels, leading to immunodeficiency. - The deficiency in IgA contributes to the recurrent sinopulmonary infections often seen in affected individuals. *Insulin resistance* - **Insulin resistance** is a known endocrine manifestation in patients with Ataxia-telangiectasia, often developing later in the disease course. - This is linked to the broader cellular dysfunction caused by the **ATM gene mutation**, which affects processes like DNA repair and cell cycle control. *Recurrent sinopulmonary infections* - Due to the associated **immunodeficiency**, particularly **IgA deficiency**, patients with Ataxia-telangiectasia are highly susceptible to recurrent sinopulmonary infections. - These infections, including **pneumonia and sinusitis**, are a significant cause of morbidity and mortality. *Lymphatic reticular malignancies* - Patients with Ataxia-telangiectasia have a significantly **increased risk of developing various cancers**, particularly **leukemias and lymphomas**. - This predisposition to malignancy is attributed to the defective **ATM gene**, which impairs DNA repair mechanisms and promotes genomic instability. *Decreased alpha-fetoprotein levels* - Ataxia-telangiectasia is actually associated with **elevated alpha-fetoprotein (AFP)** levels, not decreased levels. - **Elevated serum AFP** is a characteristic laboratory finding in A-T and serves as a useful diagnostic marker, though the mechanism is not fully understood.

Q: 10-year old male with poor growth, poor appetite, recurrent chest infection and steatorrhea is likely to have ____________ .

High sodium and chloride levels in the sweat. ***High sodium and chloride levels in the sweat*** - The constellation of poor growth, poor appetite, recurrent chest infections, and **steatorrhea** in a child is highly suggestive of **cystic fibrosis (CF)**. - **Cystic fibrosis** is characterized by defective chloride transport, leading to thick, viscous secretions in various exocrine glands, and the diagnostic hallmark is elevated **sweat chloride levels**. *Mental retardation* - While some genetic disorders causing poor growth might be associated with mental retardation, it does not directly explain **recurrent chest infections** or **steatorrhea**. - There is no direct link between mental retardation and the specific exocrine dysfunction seen in this patient's symptoms. *Recurrent skin allergy* - **Recurrent skin allergies** would present with dermatological symptoms like rash, itching, or eczema, which are not mentioned in the patient's primary complaints. - Skin allergies do not account for **poor growth**, **steatorrhea**, or frequent lung infections. *Diabetes mellitus* - **Diabetes mellitus** in children usually presents with symptoms like polyuria, polydipsia, unexplained weight loss, and fatigue, not typically recurrent chest infections or steatorrhea. - Although CF can lead to **CF-related diabetes** later in life due to pancreatic dysfunction, it's not the initial presenting symptom that encompasses all features described here. *Celiac disease* - **Celiac disease** can present with steatorrhea and poor growth due to malabsorption, but it does not typically cause **recurrent chest infections**. - The respiratory symptoms are the key distinguishing feature pointing toward cystic fibrosis rather than a purely gastrointestinal malabsorption disorder.

Q: Which of the following syndromes is associated with mental retardation?

Hunter syndrome. ***Hunter syndrome*** - Hunter syndrome (Mucopolysaccharidosis Type II) is an X-linked recessive disorder characterized by the lysosomal accumulation of **glycosaminoglycans** (dermatan sulfate and heparan sulfate). - It leads to a range of symptoms including coarse facial features, skeletal abnormalities, and **developmental delay** or **intellectual disability** in more severe forms. *Morquio syndrome B* - **Morquio syndrome B** (MPS IVB) is a lysosomal storage disorder caused by a deficiency of the enzyme **beta-galactosidase**. - While it causes skeletal abnormalities and corneal clouding, it is generally **not associated with intellectual disability**. *Natowicz syndrome* - **Natowicz syndrome** is a rare genetic disorder characterized by **spastic paraplegia** and other neurological symptoms. - It is not typically cited as a syndrome primarily associated with widespread mental retardation as a core feature. *Scheie syndrome* - **Scheie syndrome** (Mucopolysaccharidosis Type IS) is a lysosomal storage disorder caused by **alpha-L-iduronidase deficiency**. - It is the mildest form of MPS I and typically presents with skeletal abnormalities, corneal clouding, and cardiac involvement, but **intelligence is usually normal**. *Sly syndrome* - **Sly syndrome** (Mucopolysaccharidosis Type VII) is a rare lysosomal storage disorder caused by a deficiency in **beta-glucuronidase**. - While patients can have skeletal abnormalities and organomegaly, the presence and severity of **intellectual disability are variable** and generally less consistent or severe than in Hunter syndrome.

Q: 4 year old male, recurrent URTI, has difficulty breathing, High arched palate, Failure to grow and impaired hearing, management is

Referral to ENT and geneticist. ***Referral to ENT and geneticist*** - The constellation of **recurrent URTI**, **high-arched palate**, **failure to grow**, and **impaired hearing** in a 4-year-old child suggests a potential underlying craniofacial anomaly or genetic syndrome. - A **geneticist** can help diagnose underlying genetic conditions, while an **ENT specialist** can address the recurrent upper respiratory tract infections and impaired hearing, which could be related to conditions like **cleft palate** or **CHARGE syndrome**. - This is the **most appropriate initial step** for comprehensive evaluation and diagnosis. *Airway management and feeding support* - While important for immediate stabilization in some cases, these are *supportive measures* that might be necessary *after* a diagnosis is established or to manage acute crises. - They do not address the primary investigation and diagnosis of the complex symptoms presented. *Genetic testing for syndromes* - This is an integral part of the diagnostic process for many syndromes. - However, it's typically performed *after* an initial evaluation by a geneticist and often requires specific indications or panel choices based on clinical findings, rather than being the first and sole management step. *Speech and language therapy* - This is a crucial intervention if speech and language development is affected, which is likely given the impaired hearing and potential palate issues. - However, it addresses a symptom rather than the underlying cause and isn't the initial step for diagnosis or comprehensive management. *Prophylactic antibiotics and immunization* - While recurrent URTIs may warrant consideration of prophylactic measures, this approach treats symptoms without addressing the underlying cause. - Appropriate immunization should already be part of routine care, and prophylactic antibiotics don't address the structural and genetic issues causing the clinical presentation.

Q: Streak ovaries are seen in: CMC (Vellore) 09

Turner syndrome. ***Turner syndrome*** - Females with **Turner syndrome** (45, XO) often have underdeveloped, non-functional **streak ovaries** due to accelerated germ cell atresia. - This leads to **primary amenorrhea** and **infertility** due to **gonadal dysgenesis**. *Down syndrome* - **Down syndrome** (trisomy 21) is characterized by specific facial features, intellectual disability, and congenital heart defects. - While it can affect various organ systems, it is **not typically associated** with streak ovaries. *Klinefelter syndrome* - **Klinefelter syndrome** (47, XXY) affects males, leading to hypogonadism, infertility, and often gynecomastia. - It involves **testicular dysgenesis**, not ovarian abnormalities. *Kallmann syndrome* - **Kallmann syndrome** is a genetic condition characterized by **hypogonadotropic hypogonadism** (impaired production of GnRH) and **anosmia** (inability to smell). - It does not involve structural ovarian abnormalities like streak ovaries but rather a deficiency in hormonal stimulation. *Swyer syndrome* - **Swyer syndrome** (46, XY complete gonadal dysgenesis) also presents with streak gonads, but affected individuals have a **female phenotype with XY karyotype**. - Unlike Turner syndrome, these individuals have **normal stature** and lack the somatic features of Turner syndrome.

Question 1

Acrodermatitis enteropathica is:-

Accepted Answer

Inherited disorder of impaired uptake of zinc from body

Answer

Inherited disorder of excessive excretion of zinc from body

Answer

Inherited disorder of excessive excretion of copper from body

Answer

Inherited disorder of impaired uptake of copper from body

Answer

Inherited disorder of impaired excretion of zinc from body

Question 2

An 8 year old boy complains of increasing muscle weakness. On examination, his calves are bulky and show muscle tightening. His serum creatine kinase levels are increasing with age. Which of the following is the most likely diagnosis?

Accepted Answer

Dystrophin deficiency

Answer

Congenital myopathy

Answer

Myelin deficiency

Answer

Hereditary sensorimotor neuropathy

Answer

Becker muscular dystrophy

Question 3

A 7 year old boy with progressive muscle weakness and walking difficulties presented with the following finding. What is the probable diagnosis?

Accepted Answer

Duchenne muscular dystrophy

Answer

Emery-Dreifuss muscular dystrophy

Answer

Spinal muscular atrophy

Answer

Myotonic dystrophy

Answer

Becker muscular dystrophy

Question 4

A 2-year- old boy presents with progressive clumsiness and difficulty walking. On physical examination, the child has
large calves. He has difficulty walking on his toes and has a waddling gait as shown. Which of the following is the most likely diagnosis?

Accepted Answer

Duchenne muscular dystrophy

Answer

Myotonic dystrophy

Answer

Facioscapulo humeral dystrophy

Answer

Becker muscular dystrophy

Answer

Limb-girdle muscular dystrophy

Question 5

Ataxia telangiectasia is associated with all of the following except:

Accepted Answer

Increased fraction of IgA immunoglobulins

Answer

Insulin resistance

Answer

Recurrent sinopulmonary infections

Answer

Lymphatic reticular malignancies

Answer

Decreased alpha-fetoprotein levels

Question 6

10-year old male with poor growth, poor appetite, recurrent chest infection and steatorrhea is likely to have ____________ .

Accepted Answer

High sodium and chloride levels in the sweat

Answer

Mental retardation

Answer

Recurrent skin allergy

Answer

Diabetes mellitus

Answer

Celiac disease

Question 7

Which of the following syndromes is associated with mental retardation?

Accepted Answer

Hunter syndrome

Answer

Morquio syndrome B

Answer

Natowicz syndrome

Answer

Sly syndrome

Answer

Scheie syndrome

Question 8

A 7-year-old boy has demineralized bones with pseudofractures. Physiologic doses of vitamin D do not result in improvement. Which of the following is most likely to be associated with this syndrome?

Accepted Answer

low 1,25(OH)2 vitamin D levels

Answer

alopecia

Answer

osteoporosis

Answer

hyperphosphatemia

Answer

elevated parathyroid hormone (PTH)

Question 9

4 year old male, recurrent URTI, has difficulty breathing, High arched palate, Failure to grow and impaired hearing, management is

Accepted Answer

Referral to ENT and geneticist

Answer

Airway management and feeding support

Answer

Genetic testing for syndromes

Answer

Speech and language therapy

Answer

Prophylactic antibiotics and immunization

Question 10

Streak ovaries are seen in: CMC (Vellore) 09

Accepted Answer

Turner syndrome

Answer

Down syndrome

Answer

Klinefelter syndrome

Answer

Kallmann syndrome

Answer

Swyer syndrome

Genetic and Metabolic Disorders — MCQs

Genetic and Metabolic Disorders — MCQs

On this page

Practice by Chapter

Want unlimited practice?