Other Well-Defined Immunodeficiencies

Combined immunodeficiencies with associated or syndromic features have a less profound immunophenotype than severe combined immunodeficiencies. Nevertheless, the associated syndromic features can make diagnosis and treatment challenging. Whilst treatment options for severe combined immunodeficiencies are clearly defined (hematopoietic stem cell transplantation or gene therapy), the optimal management of the disorders described in the following chapter has not been clearly delineated in every case. Indeed, for some of the very rare diseases described, there is not enough information currently available to definitively proclaim the optimum treatment approaches. Furthermore, whilst treatment may resolve the immunodeficiency, the underlying genetic defect may complicate treatment options (as in the DNA repair defects), or may leave the associated non-immunological features unchanged (as in the Hyper IgE or ICF syndromes). This chapter describes many combined immunodeficiencies with associated or syndromic features, and outlines presentation, investigation and current management recommendations.