Genetics and Disease Practice Questions

Q: Which of the following statements about alpha-1 antitrypsin deficiency is true?

May cause cholestatic jaundice. ***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.

Q: Which of the following is a single gene autosomal recessive disease?

Wilson's disease. ***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**.

Q: Which of the following statements about gene therapy is false?

Gene therapy is only used for genetic disorders.. ***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].

Q: Holt-Oram syndrome is caused by a mutation of?

TBX5. ***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.

Q: Which of the following is a polygenic disorder?

Hypertension. ***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].

Q: Which of the following conditions is not inherited in an autosomal dominant manner?

Albinism. ***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.

Q: All are true regarding Klinefelter's syndrome except for which of the following?

Webbing of neck. ***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].

Q: Mutation in the NPHS1 gene causes which of the following disease?

Congenital Finnish type nephrotic syndrome. ***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.

Q: Which one of the following is an autosomal dominant disorder?

Hereditary spherocytosis. ***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].

Q: What specific hand abnormalities are associated with Marfan syndrome?

Arachnodactyly. ***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.

Question 1

Which of the following statements about alpha-1 antitrypsin deficiency is true?

Accepted Answer

May cause cholestatic jaundice

Question 2

Which of the following is a single gene autosomal recessive disease?

Accepted Answer

Wilson's disease

Answer

Tuberous sclerosis

Answer

Huntington's disease

Answer

Schizophrenia

Question 3

Which of the following statements about gene therapy is false?

Accepted Answer

Gene therapy is only used for genetic disorders.

Answer

Gene also considered as drug

Answer

Gene therapy can be used to treat some cancers.

Answer

Has been tried in cystic fibrosis

Question 4

Holt-Oram syndrome is caused by a mutation of?

Accepted Answer

TBX5

Answer

NKX2.5

Answer

Lefty

Answer

None of the options

Question 5

Which of the following is a polygenic disorder?

Accepted Answer

Hypertension

Answer

Cystic fibrosis

Answer

Phenylketonuria

Answer

Multiple sclerosis

Question 6

Which of the following conditions is not inherited in an autosomal dominant manner?

Accepted Answer

Albinism

Answer

Von - Hippel Lindau syndrome

Answer

Marfan's syndrome

Answer

Familial adenomatous polyposis

Question 7

All are true regarding Klinefelter's syndrome except for which of the following?

Accepted Answer

Webbing of neck

Answer

Gynecomastia

Answer

Increased FSH levels

Answer

Small Testes

Question 8

Mutation in the NPHS1 gene causes which of the following disease?

Accepted Answer

Congenital Finnish type nephrotic syndrome

Answer

Alport syndrome

Answer

Focal segmental glomerulonephritis

Answer

nail patella syndrome

Question 9

Which one of the following is an autosomal dominant disorder?

Accepted Answer

Hereditary spherocytosis

Answer

Cystic fibrosis

Answer

Sickle cell anemia

Answer

G-6PD deficiency

Question 10

What specific hand abnormalities are associated with Marfan syndrome?

Accepted Answer

Arachnodactyly

Answer

Brachydactyly

Answer

Clinodactyly

Answer

Syndactyly

Genetics and Disease — MCQs

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