Genetics and Disease — MCQs
On this page
Which of the following statements about alpha-1 antitrypsin deficiency is true?
Which of the following is a single gene autosomal recessive disease?
Holt-Oram syndrome is caused by a mutation of?
Which of the following statements about gene therapy is false?
Which of the following is a polygenic disorder?
Which of the following conditions is not inherited in an autosomal dominant manner?
All are true regarding Klinefelter's syndrome except for which of the following?
Mutation in the NPHS1 gene causes which of the following disease?
Which one of the following is an autosomal dominant disorder?
What specific hand abnormalities are associated with Marfan syndrome?
Genetics and Disease Indian Medical PG Practice Questions and MCQs
Question 291: Which of the following statements about alpha-1 antitrypsin deficiency is true?
- A. May cause cholestatic jaundice (Correct Answer)
- B. Autosomal recessive (Correct Answer)
- C. Deficiency of protease inhibitor (Correct Answer)
- D. All of the above (Correct Answer)
Explanation: ***All of the above*** - All listed statements accurately describe aspects of **alpha-1 antitrypsin deficiency** [1], including its nature, genetic inheritance, and potential consequences. - This condition allows **proteolytic enzymes** to damage the lungs and liver [1], among other organs, confirming all options as true. *Deficiency of protease inhibitor* - While alpha-1 antitrypsin is a **protease inhibitor** [1], the wording can be confusing as it implies a more general condition rather than specifying the genetic aspect of **alpha-1 antitrypsin deficiency**. - This oes not encompass the full clinical implications of the deficiency, making it insufficient alone to describe the condition. *Autosomal recessive* - The inheritance pattern of alpha-1 antitrypsin deficiency is actually **autosomal co-dominant**, not strictly recessive. - This means that individuals can express both normal and abnormal alleles, which this option fails to capture accurately. *May cause cholestatic jaundice* - Though **cholestatic jaundice** can occur due to liver involvement in severe cases, it is not a defining feature of the deficiency and may be considered as a rare complication. - More commonly, the condition leads to **emphysema** [1][2] and liver cirrhosis, highlighting the insufficiency of this statement on its own.
Question 292: Which of the following is a single gene autosomal recessive disease?
- A. Wilson's disease (Correct Answer)
- B. Tuberous sclerosis
- C. Huntington's disease
- D. Schizophrenia
Explanation: ***Wilson's disease*** - This is an **autosomal recessive disorder** [1] characterized by excessive **copper accumulation** in the liver, brain, and other organs due to a mutation in the ATP7B gene. - Manifestations include **hepatic dysfunction**, neurological symptoms, and characteristic **Kayser-Fleischer rings** in the eyes [1]. *Tuberous sclerosis* - This is an **autosomal dominant disorder** caused by mutations in the TSC1 or TSC2 genes, leading to the formation of benign tumors in multiple organs. - Clinical features include **epilepsy**, intellectual disability, facial angiofibromas, and renal angiomyolipomas. *Huntington's disease* - This is an **autosomal dominant neurodegenerative disorder** caused by a CAG trinucleotide repeat expansion in the HTT gene. - It presents with **progressive chorea**, psychiatric symptoms, and cognitive decline, typically in mid-adulthood. *Schizophrenia* - This is a **complex psychiatric disorder** with a multifactorial etiology, involving a combination of genetic predisposition and environmental factors. - It is not a single gene disorder but rather involves many genes contributing to risk, indicating a **polygenic inheritance pattern**.
Question 293: Holt-Oram syndrome is caused by a mutation of?
- A. TBX5 (Correct Answer)
- B. NKX2.5
- C. Lefty
- D. None of the options
Explanation: ***TBX5*** - **Holt-Oram syndrome** is an **autosomal dominant** disorder characterized by abnormalities of the heart and upper limbs. - It is caused by a mutation in the **TBX5 gene**, which encodes a **T-box transcription factor** essential for cardiac and limb development. *NKX2.5* - Mutations in the **NKX2.5 gene** are associated with various **congenital heart defects**, particularly **atrial septal defects** and **ventricular septal defects**, often with conduction abnormalities. - Unlike Holt-Oram, it is not typically linked to the characteristic **radial ray limb anomalies**. *Lefty* - The **LEFTY genes (LEFTY1 and LEFTY2)** are involved in establishing **left-right asymmetry** during embryonic development. - Mutations in these genes are associated with conditions like **heterotaxy syndromes**, where organs are abnormally positioned, but not directly with Holt-Oram syndrome. *None of the options* - This option is incorrect because **TBX5** is definitively associated with Holt-Oram syndrome.
Question 294: Which of the following statements about gene therapy is false?
- A. Gene also considered as drug
- B. Gene therapy can be used to treat some cancers.
- C. Has been tried in cystic fibrosis
- D. Gene therapy is only used for genetic disorders. (Correct Answer)
Explanation: ***Gene therapy is only used for genetic disorders.*** - This statement is **false** because gene therapy has applications beyond just genetic disorders. It is also being explored and used in the treatment of acquired diseases such as **cancer** and **infectious diseases**. - While it's a prominent approach for correcting genetic defects, its scope is much broader, involving the introduction or modification of genes to achieve a therapeutic effect in various conditions. *Gene also considered as drug* - This statement is **true**. Gene therapy products are often regulated as **drugs** or **biological products** by regulatory bodies like the FDA. - This is because they involve the delivery of genetic material that acts to modify gene expression or cell function to produce a therapeutic effect, similar to how traditional drugs work. *Has been tried in cystic fibrosis* - This statement is **true**. Gene therapy has been extensively investigated as a potential treatment for **cystic fibrosis (CF)**. - CF is caused by mutations in the **CFTR gene**, and researchers have attempted to deliver functional copies of this gene to the affected cells, particularly in the lungs, to correct the underlying defect. *Gene therapy can be used to treat some cancers.* - This statement is **true**. Gene therapy is an active area of research and treatment for various **cancers** [1]. - Approaches include introducing genes that make cancer cells more susceptible to chemotherapy, enhancing the immune system's ability to fight cancer, or directly killing cancer cells through gene delivery [1].
Question 295: Which of the following is a polygenic disorder?
- A. Cystic fibrosis
- B. Phenylketonuria
- C. Multiple sclerosis
- D. Hypertension (Correct Answer)
Explanation: ***Hypertension*** - **Hypertension** is a classic example of a **polygenic disorder**, meaning it is influenced by multiple genes acting together, often in combination with environmental factors. - The inheritance pattern is **complex and multifactorial**, making it difficult to predict based on a single genetic marker. *Cystic fibrosis* - **Cystic fibrosis** is a **monogenic disorder** caused by mutations in a single gene, the **CFTR gene** [1]. - It follows an **autosomal recessive** inheritance pattern, meaning two copies of the mutated gene are required for the disease to manifest [1]. *Phenylketonuria* - **Phenylketonuria (PKU)** is also a **monogenic disorder** caused by a mutation in the **PAH gene**, leading to a deficiency of the enzyme **phenylalanine hydroxylase**. - It is an **autosomal recessive** disorder, requiring two copies of the mutated gene. *Multiple sclerosis* - **Multiple sclerosis** is considered a **complex, multifactorial disorder** with both genetic and environmental components [1]. - While there is a genetic predisposition, it does not strictly fit the definition of a simple polygenic disorder where multiple genes directly cause the disease; instead, it involves interactions between many genes and the environment [1].
Question 296: Which of the following conditions is not inherited in an autosomal dominant manner?
- A. Von - Hippel Lindau syndrome
- B. Marfan's syndrome
- C. Albinism (Correct Answer)
- D. Familial adenomatous polyposis
Explanation: ***Albinism*** - Albinism is typically inherited in an **autosomal recessive** manner [2], not autosomal dominant. - It is caused by mutations in genes responsible for **melanin production**, leading to a lack of pigment in skin, hair, and eyes [2]. *Familial adenomatous polyposis* - This condition is an **autosomal dominant** disorder [1] characterized by the development of numerous polyps in the colon. - It is caused by mutations in the **APC** gene, significantly increasing the risk for colorectal cancer. *Von - Hippel Lindau syndrome* - Von Hippel Lindau syndrome is also an **autosomal dominant** disorder [1], associated with tumors in various organs, including hemangioblastomas and renal cell carcinoma. - This condition is caused by mutations in the **VHL** gene, leading to abnormal blood vessel growth. *Marfan's syndrome* - Marfan's syndrome is an **autosomal dominant** connective tissue disorder that affects various systems in the body, particularly the cardiovascular system. - It is caused by mutations in the **FBN1** gene, leading to tall stature, long limbs, and heart-related complications.
Question 297: All are true regarding Klinefelter's syndrome except for which of the following?
- A. Webbing of neck (Correct Answer)
- B. Gynecomastia
- C. Increased FSH levels
- D. Small Testes
Explanation: ***Webbing of neck*** - **Webbing of the neck** is associated with Turner syndrome [2], not Klinefelter's syndrome, making it an incorrect statement regarding the latter [4]. - Klinefelter's syndrome typically does **not** feature neck webbing as a clinical sign. *Gynecomastia* - Gynecomastia is a common feature in Klinefelter's syndrome due to **hormonal imbalances**, leading to breast tissue development [1]. - It is seen in many affected individuals and is therefore an accurate statement regarding the syndrome. *Increased FSH levels* - Patients with Klinefelter's syndrome often exhibit **elevated FSH levels** due to primary testicular failure [1]. - This happens because the Sertoli cells are unable to support spermatogenesis, resulting in increased FSH as a compensatory mechanism [3]. *Small Testes* - Small testes (hypogonadism) are a hallmark of Klinefelter's syndrome due to the disruption of normal testicular function [1]. - This condition results in underdeveloped testicular tissue owing to the extra X chromosome [1].
Question 298: Mutation in the NPHS1 gene causes which of the following disease?
- A. Alport syndrome
- B. Focal segmental glomerulonephritis
- C. nail patella syndrome
- D. Congenital Finnish type nephrotic syndrome (Correct Answer)
Explanation: ***Congenital Finnish type nephrotic syndrome*** - This syndrome is caused by mutations in the **NPHS1 gene**, encoding **nephrin**, a key component of the **slit diaphragm** in glomerular podocytes. - The dysfunctional nephrin leads to severe **proteinuria** and nephrotic syndrome from birth. *Alport syndrome* - This syndrome is caused by mutations in genes encoding **Type IV collagen**, primarily **COL4A5 (X-linked)**, which is crucial for basement membrane integrity [3]. - Characterized by **hematuria**, progressive renal failure, **sensorineural hearing loss**, and ocular abnormalities. *Focal segmental glomerulonephritis* - While some forms can be genetic, **NPHS1 mutations** are not typically the primary cause of genetic [1]. - This condition involves scarring of specific parts of some glomeruli and has various primary and secondary causes [2]. *Nail patella syndrome* - This syndrome is caused by mutations in the **LMX1B gene**, which plays a role in early limb and kidney development. - It is characterized by **nail dysplasia**, absent or hypoplastic patellae, elbow abnormalities, and iliac horns, sometimes with renal involvement.
Question 299: Which one of the following is an autosomal dominant disorder?
- A. Cystic fibrosis
- B. Hereditary spherocytosis (Correct Answer)
- C. Sickle cell anemia
- D. G-6PD deficiency
Explanation: ***Hereditary spherocytosis*** - It is characterized by **autosomal dominant inheritance** [1], leading to the destruction of red blood cells. - Mutations in proteins that maintain the **red blood cell membrane** integrity result in spherocyte formation [1]. *Cystic fibrosis* - This condition follows a **autosomal recessive inheritance pattern**, requiring two copies of the mutated gene for disease manifestation. - It is caused by mutations in the **CFTR gene**, affecting chloride transport and leading to thick secretions. *G-6PD deficiency* - This disorder is inherited in an **X-linked recessive manner** [2], primarily affecting males and transmitted through carrier females. - Characterized by **hemolytic anemia** triggered by certain medications or infections, it does not follow dominant inheritance [2]. *Sickle cell anemia* - Sickle cell anemia is also an **autosomal recessive disorder** [3], meaning affected individuals must inherit two copies of the sickle cell gene. - It results in a mutation in the **HBB gene**, leading to the production of abnormal hemoglobin (HbS) [3].
Question 300: What specific hand abnormalities are associated with Marfan syndrome?
- A. Brachydactyly
- B. Clinodactyly
- C. Syndactyly
- D. Arachnodactyly (Correct Answer)
Explanation: ***Arachnodactyly*** - This term refers to **long, slender fingers and toes**, resembling a spider's appendages, which is a classic musculoskeletal manifestation of **Marfan syndrome**. - It results from the generalized connective tissue disorder affecting the deposition of **fibrillin-1**, leading to excessive bone growth. *Syndactyly* - This condition involves the **fusion of adjacent digits**, either soft tissue or bone, rather than unusually long fingers. - It is typically a congenital anomaly not specifically associated with Marfan syndrome. *Clinodactyly* - This describes the **curving or deviation of a digit**, usually the fifth finger, due to an abnormally shaped bone [1]. - While a digital anomaly, it is not a hallmark feature of Marfan syndrome, which is characterized by digit length. *Brachydactyly* - This condition is characterized by **unusually short fingers and toes**, which is the opposite of the digital characteristic seen in Marfan syndrome. - It can be a feature of various genetic disorders but not Marfan syndrome.
Practice by Chapter
Principles of Medical Genetics
Practice Questions
Genetic Testing and Counseling
Practice Questions
Single Gene Disorders
Practice Questions
Chromosomal Disorders
Practice Questions
Mitochondrial Diseases
Practice Questions
Pharmacogenomics
Practice Questions
Cancer Genetics
Practice Questions
Genetics of Common Diseases
Practice Questions
Epigenetics and Disease
Practice Questions
Genetic Basis of Developmental Disorders
Practice Questions
Ethical Issues in Medical Genetics
Practice Questions
Gene Therapy and Precision Medicine
Practice Questions
Want unlimited practice?
Get full access to all questions, explanations, and performance tracking.
Start For Free