Mode of Inheritance and Single gene disorders

By Nur Syahirah Zakaria,

1. If both parent pass along a particular defective gene, their child will have a
chance of developing cystic fibrosis.

2. Life expectancy for cystic fibrosis sufferers has not changed since the
disease was first described.

3. People with Huntington's disease are sterile.

4. Haemophilia is a group of blood-clotting disorders.

5. The blood of a haemophiliac has difficulting in clotting, leading to excessive
bleeding.

6. Sickle cell disease is so named because the mutated gene responsible is shaped
like a sickle.

7. Neurofibromatosis is a group of genetic disorders characterised by the growth
of tumors throughout the nervous system.

8. Neurofibromatosis is not usually fatal.

9. Muscular dystrophy encompasses a range of almost identical muscular disorders.

10. Turner syndrome is a chromosomal condition related to the X chromosomes that
alters development in females.

11. A gene is a length of DNA.

12. There is such a thing as a longevity gene which enable you to live up to 30%
longer than the average human.

13. Identical twins have the same genes.

14. Genes are passed down through your biological parents.

15. In autosomal dominant inheritance, only one copy of a disease allele is
necessary for an individual to be susceptible to expressing the phenotype.

16. Autosomal dominant inheritance is often called horizontal inheritance because
of the transmission from parent to offspring.

17. Example of disease with autosomal dominant inheritance include muscular
dystrophy and Huntington's disease.

18. In autosomal recessive inheritance, two copies of a disease allele are

required for an individual to express the phenotype.

19. Sickle cell anemia and cystic fibrosis is autosomal dominant inheritance.

20. As in autosomal dominant inheritance, only one copy of a disease allele on

the X chromosome is required for an individual to be susceptible to an X-linked
dominant disease.

21. Example of disease with X-linked recessive inheritance include Duchenne

muscular dystrophy.

22. Complex disorders are caused by mutation of genes.

23. Complex disorders are also known as multifactorial disorder.

24. Autosomal dominant inheritance can be observed in male-to-male transmission.

25. Across the population, the autosomal recessive inheritance and autosomal
dominant inheritance are not equally affecting male and female.

Answers
1. T, 2. F, 3. F, 4. T, 5. T
6. F, 7. T, 8. T, 9. T, 10. T,
11. T, 12. F, 13. T, 14. T, 15. T,
16. F, 17. T, 18. T, 19. F, 20. T,
21. T, 22. F, 23. T, 24. T, 25. F