Question

Aplastic anemia may be caused by Fanconi anemia, which occurs due to a dsDNA repair defect, resulting in bone marrow failure. What is the defect in homologous recombination (double stranded break repair)?

1) Defect in mismatch repair
2) Defect in nucleotide excision repair
3) Defect in base excision repair
4) Defect in homologous recombination

Answer 1

Fanconi anemia can cause aplastic anemia due to a defect in the homologous recombination DNA repair mechanism. This defect prevents proper repair of double-stranded DNA breaks which is essential for maintaining bone marrow function that produces blood cells.

Step-by-step explanation:

Fanconi anemia is a genetic disorder that leads to aplastic anemia due to a defect in homologous recombination, a critical process used for repairing double-stranded DNA breaks. This defect falls under the fourth category, which is a defect in homologous recombination itself.

Aplastic anemia can result from the inheritance of conditions like Fanconi anemia, but it can also arise from environmental factors such as radiation, medication, chemotherapy, or infections. This condition signifies bone marrow failure where the marrow is unable to produce a sufficient number of blood cells, including red blood cells (RBCs), white blood cells (WBCs), and platelets. The treatment for aplastic anemia sometimes involves methods to 'reboot' the immune system which can help in the recovery of bone marrow function.