Biology

Human Genetics and Disorders

844 Questions

Human Genetics and Disorders covers the inheritance patterns, genetic mutations, and molecular basis of hereditary diseases. Topics include sex-linked traits, cancer genetics, and metabolic disorders. This section tests knowledge critical for biology exams and general science papers.

Genetic mutationsInherited disordersCancer geneticsGenetic testingMendelian inheritance

Human Genetics and Disorders Questions

Multiple choice

Which of the following is the result of 4p deletion?

  1. Wolf-Hirschhorn syndrome

  2. Rubinstein-Taybi syndrome

  3. Angelman syndrome

  4. Cri du chat syndrome
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Wolf-Hirschhorn syndrome is a characteristic phenotype resulting from a partial deletion of chromosomal material of the short arm of chromosome 4 (4p deletion).

Multiple choice

What is the significance of CONDEL deletion mutations?

  1. They are responsible for immediate abortion.

  2. They are responsible for Cri du chat syndrome.

  3. They are responsible for evolutionary differences.

  4. They are responsible for spinal muscular dystrophy.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

hCONDEL deletions might be responsible for the evolutionary differences present among closely related species. Such deletions in humans are referred to as hCONDELs. They may be responsible for the anatomical and behavioral differences between humans, chimpanzees and other mammals.

Multiple choice

Which of the following diseases is caused by gene amplification?

  1. AIDS

  2. Cancer

  3. William's syndrome

  4. Duschenne muscular dystrophy
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Amplification or duplications of oncogenes are a common cause of many types of cancer. In such cases, the genetic duplication occurs in somatic cells and affects only the genome of cancer cells.

Multiple choice

Which of the following is caused by mutation in merlin (tumor suppressor) gene?

  1. Neurofibromatosis type I

  2. Neurofibromatosis type II

  3. Miller-Dieker syndrome

  4. Smith-Magenis syndrome
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Neurofibromatosis type (NF-II) is caused by mutations of the merlin gene. The main manifestation of the disease is the development of symmetric, non-malignant brain tumors in the region of the cranial nerve VIII, which is the auditory-vestibular nerve that transmits sensory information from the inner ear to the brain.

Multiple choice

Lactose intolerance is the inability of an individual to digest lactose, which is a prominent sugar found in milk. Which among the following statements regarding this disease is false?

  1. Primary lactase deficiency is caused by the absence of a lactase persistence allele.

  2. Lactose intolerance is not an allergy.

  3. Congenital lactase deficiency is an autosomal recessive genetic disorder.

  4. Secondary lactase deficiency is an inherited genetic disorder.

  5. Lactose intolerance is caused by insufficient levels of lactase in the lining of the duodenum.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Secondary, acquired or transient lactase deficiency is caused by an injury to the small intestine, usually during infancy, from acute gastroenteritis, diarrhea, chemotherapy, intestinal parasites or other environmental causes.

Multiple choice

In humans the TYMP gene encodes the enzyme thymidine phosphorylase. The mitochondrial disease caused by mutations in the TYMP gene is _________________.

  1. mitochondrial neurogastrointestinal encephalopathy syndrome

  2. Leigh disease

  3. multiple sclerosis

  4. Wolff-Parkinson-White syndrome

  5. diabetes mellitus and deafness
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Mitochondrial neurogastrointestinal encephalopathy syndrome is a rare autosomal recessive mitochondrial disease. Unlike typical mitochondrial diseases caused by mitochondrial DNA (mtDNA) mutations, MNGIE is caused by mutations in the TYMP gene, which encodes the enzyme thymidine phosphorylase.

Multiple choice

The mutation in the haemoglobin gene causes _________________.

  1. phenylketonuri

  2. cystic fibrosis

  3. sickle-cell disease

  4. Tay–Sachs disease

  5. haemophilia
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Sickle-cell disease is a hereditary blood disorder, characterized by red blood cells that assume an abnormal, rigid sickle shape. Sickling decreases the cells' flexibility and results in a risk of various life-threatening complications. This sickling occurs because of a mutation in the haemoglobin gene.

Multiple choice

Which among the following genetic diseases is not inherited?

  1. 47, XYY

  2. 47, XX, +21

  3. 47, XXY

  4. 45, X

  5. 1p36 deletion syndrome
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

47, XYY is not inherited but usually occurs as a random event during the formation of sperm cells. An incident in chromosome separation during anaphase II (of meiosis II) called nondisjunction can result in sperm cells with an extra copy of the Y-chromosome. If one of these atypical sperm cells contributes to the genetic makeup of a child, the child will have an extra Y-chromosome in each of the body's cells.