The correct option is B Dysfunction of immune system
Adenosine deaminase deficiency (ADA deficiency) is caused due to the deletion of the gene responsible for the production of ADA (adenosine deaminase) enzyme.
The ADA enzyme is crucial for the immune system to function.
Lymphocytes are important cells of the immune system and help protect the body from infections. The patients suffering from ADA deficiency have non-functional lymphocytes and so they cannot mount immune responses against invading pathogens.
Hence, adenosine deaminase deficiency results in the dysfunction of the immune system.
Parkinson’s disease is a neurological disorder that affects movement.
Hyposecretion of adrenal hormones such as cortisol causes Addison’s disease.
ADA deficiency does not cause digestive disorders.