What causes CID?

CID is usually an inherited condition, passed on in families in a similar way
to physical characteristics, such as eye colour. It is caused by a mistake (or
‘mutation’) in a child’s genetic make-up. PID UK has a separate information
leaflet devoted to the genetics of primary immunodeficiency.  Specialists in
genetics and genetic counselling are also on hand to talk through the inheritance
of CID with you if needed.

The immune system relies on a large number of genes for its normal
development. In children affected by CID, a defect in one or more of these
genes results in the absence or malfunction of a protein necessary for normal
functioning of the immune system. Different types of CID are named based
on the particular protein or gene that is affected or sometimes the doctor(s)
who first described it. Some of the better-known types include Wiskott-Aldrich
syndrome, DOCK8 deficiency and recombination activating gene (RAG)
deficiency. It is helpful to know the exact cause: (a) because in some conditions
there may be specific treatments available, and (b) to allow accurate genetic
counselling for future pregnancies.

Reviewed November 2017