Question

A 20-year-old African-American male presents to the ER with severe abdominal, low back, and rib pain. He has had similar episodes all his life. Blood work reveals severe microcytic, hypochromic anemia. A peripheral smear shows abnormally shaped red blood cells and a hemoglobin electrophoresis confirms his abnormality.

If the above patient has children with a partner with normal hemoglobin genes, which one of the following patterns will occur?
(A) All sons will have the same disease as the father, while all daughters will be carriers.
(B) All children will have the same disease as the father.
(C) All children will be carriers for the disease (contain the mutated gene, but do not express the disease phenotype).
(D) All children will have normal hemoglobin, like their mother.
(E) All daughters will have the same disease as their father, while all sons will be carriers.

Answer 1

A 20-year-old male with sickle cell anemia has a 50% chance of passing the mutant gene to his children. If the mother has normal hemoglobin genes, all children will be carriers (heterozygous) for sickle cell anemia, with each carrying one mutated gene and one normal gene.

Step-by-step explanation:

The scenario describes a 20-year-old African-American male with severe microcytic, hypochromic anemia and a peripheral smear showing sickle-shaped red blood cells, which is characteristic of sickle cell anemia. Sickle cell anemia is an autosomal recessive disorder, meaning that two copies of the mutated gene are needed for a person to express the disease phenotype. If the patient's partner has normal hemoglobin genes (meaning she is homozygous for the normal allele), their children will each have a 50% chance of inheriting one sickle cell gene from the father and one normal gene from the mother, making them carriers (heterozygous) for the disease. The correct pattern of inheritance for the children in this scenario is option (C): All children will be carriers for the disease.