title: Adenosine deaminase deficient severe combined immunodeficiency presenting as atypical haemolytic uraemic syndrome.
abstract: OBJECTIVE
  Adenosine deaminase (ADA) deficiency is a systemic disorder of purine metabolism. Deficiency of the purine salvage enzyme ADA leads to the build-up of the toxic metabolites, deoxyadenosine triphosphate and deoxyadenosine. ADA is ubiquitously expressed in all tissues of the body but most profoundly affects lymphocyte development and function leading to severe combined immunodeficiency (SCID). Unlike most other forms of SCID, ADA deficiency also results in non-immunologic manifestations. Associations between ADA deficiency and sensorineural hearing loss, behavioural abnormalities, non-infectious pulmonary disease and skeletal dysplasia are all recognised, and affect the long term outcome for these patients. Identification of new non-immunological manifestations and clinical presentations of ADA deficiency is essential to allow early optimisation of supportive care.
  
  
  RESULTS
  Here we report four patients with ADA deficiency whose presenting feature was haemolytic uremic syndrome (HUS). 3 of 4 patients were diagnosed with ADA deficiency only after developing HUS, and one diagnosis was made post mortem, after a sibling was diagnosed with SCID. Shiga-toxigenic organisms were not isolated from any of the patients. 2 patients made a good recovery from their HUS with supportive treatment and initiation of PEG-ADA. Both remain well on enzyme replacement with mild or no residual renal impairment.
  
  
  CONCLUSIONS
  Clinicians should be aware of this previously unreported non-immunologic manifestation of ADA deficiency.
authors: Department of Clinical Immunology and Bone Marrow Transplantation, Great Ormond Street Hospital National Health Service Trust, London, UK.
authors: Olga
authors: O
authors: Nikolajeva
authors: Austen
authors: A
authors: Worth
authors: Rosie
authors: R
authors: Hague
authors: Nuria
authors: N
authors: Martinez-Alier
authors: Joanne
authors: J
authors: Smart
authors: Stuart
authors: S
authors: Adams
authors: E Graham
authors: EG
authors: Davies
authors: H Bobby
authors: HB
authors: Gaspar
mesh_terms: D000243:Adenosine Deaminase / Q000172:deficiency* / Q000235:genetics; D000361:Agammaglobulinemia / Q000175:diagnosis* / Q000188:drug therapy; D065766:Atypical Hemolytic Uremic Syndrome / Q000175:diagnosis*; D002648:Child; D003937:Diagnosis, Differential; D017809:Fatal Outcome; D005260:Female; D005838:Genotype; D006801:Humans; D007223:Infant; D008297:Male; D009154:Mutation; D016511:Severe Combined Immunodeficiency / Q000175:diagnosis* / Q000188:drug therapy
chemical_list: D000243:Adenosine Deaminase