Which of the following diseases can be inherited?

Step 1: Analyze the question The question asks which disease can be inherited, meaning passed from parents to offspring through genes, not caught from the environment or from other people.

Step 2: Explain the concept Diseases fall into two broad groups:

• Infectious (communicable) diseases are caused by pathogens such as bacteria, viruses, or protozoa. They are spread by contact, air, water, or vectors.
• Genetic (hereditary) diseases are caused by faulty genes or chromosomes passed from parents to children through gametes.

Step 3: Check each option

• A. Pneumonia is an infection of the lungs caused by bacteria or viruses. It is not inherited.
• B. Whooping cough (pertussis) is caused by the bacterium Bordetella pertussis and spreads through droplets. It is not inherited.
• C. Sickle cell anaemia is caused by a mutation in the gene for haemoglobin. A child develops the disease (genotype SS) when both parents pass on the sickle cell gene (S). It is inherited.
• D. Malaria is caused by the protozoan Plasmodium and transmitted by the female Anopheles mosquito. It is not inherited.

Step 4: Answer The correct option is C. Sickle cell anaemia.

Quick note for Nigerian students: If both parents are carriers (AS × AS), each child has a 25% chance of being AA (normal), a 50% chance of being AS (carrier), and a 25% chance of being SS (sickle cell disease).

Exam tip: When you see "inherited" or "hereditary", look for genetic conditions like sickle cell anaemia, haemophilia, albinism, or colour blindness. Diseases caused by germs, such as bacteria, viruses, or protozoa, are not inherited. Remember: germs = caught, genes = inherited.