Consanguinity and primary immunodeficiencies.
Primary immunodeficiencies (PIDs) are a heterogeneous group of genetic disorders caused by defects in the immune system that predispose patients to infections, autoimmune diseases, lymphoproliferation and malignancies. Most PIDs are inherited in an autosomal recessive pattern; therefore, they are more common in areas with high rates of consanguineous marriage. Reports about PIDs from these areas have demonstrated a peculiar prevalence of more severe forms of diseases compared to other regions, and patients born to consanguineous parents have increased rates of morbidity and mortality compared to other patients. Individuals at high risk of having a child with a PID who wish to have a healthy child have limited options, these include prenatal diagnosis and pre-implantation genetic diagnosis. However, these options require a collaborative team of specialists and may not always be implemented due to geographic, religious, financial or social factors. The recent introduction of newborn-screening programs for a number of T and B lymphocyte deficiencies will facilitate early diagnosis and therapeutic interventions, which may include hematopoietic stem cell transplantation and intravenous immunoglobulin treatment. There is a need for the implementation of strategies to increase public awareness of the health risks associated with consanguineous marriage. It should be stressed that genetic counseling should be an important component of the care of patients with PIDs as well as their families.