Signs, symptoms and diagnosis

The signs and symptoms in babies with X-SCID are the same as in all forms of
SCID. You can find an overview here.


Initial investigations are the same as for all forms of SCID and are described here.

There are a number of features that might suggest a diagnosis of X-SCID. A detailed family history is important. If the baby is a boy and there is a history of affected boys in the family (including unexplained infant deaths), X-SCID may be likely. In addition, the basic immunology tests looking at the presence of T, NK and B cells may show a pattern suggestive of X-SCID. The pattern doctors are looking for is ‘T- B+ NK-’, meaning that T cells and NK cells are absent or very low in number, while B cells are present in normal numbers. If this pattern is confirmed, particularly when the family history is suggestive, X-SCID is likely.

The next step is to perform specialised tests to look for the γc protein and to carry out genetic testing to look for a mutation in the γc gene. Results of these tests are usually available within a few days.

Reviewed October 2017