Israel Medical Association Journal

Background: Deficiency of adenosine deaminase 2 (DADA2) is a rare autosomal recessive disorder caused by loss-of-function mutations in the ADA2 gene, with a broad phenotype spanning systemic vasculitis, hematologic, immune deficiency, and autoinflammatory manifestations.

Objectives: To describe a decade of DADA2 management within a uniquely diverse population.

Methods: We conducted a single-center retrospective cohort study of genetically confirmed DADA2 patients (2014–2024). Demographics, clinical manifestations, laboratory findings, treatments, and long-term outcomes were reviewed.

Results: Seventeen pediatric patients were included from two ethnic groups: Arab Muslim (12/17, 70%) and Georgian Jewish (5/17, 29%). The median age at symptom onset was 3.5 months and at diagnosis 4 years. Phenotypes were purely vasculitic/inflammatory (5/17), purely hematologic (3/17), mixed hematologic-inflammatory (6/17), or mixed hematologic-immunodeficiency (3/17). None had isolated immune deficiency. The purely vasculitic/inflammatory phenotype was confined to Georgian Jewish patients, all homozygous for p.Gly47Arg, presenting with cutaneous and ischemic manifestations. Twelve patients received TNF-α inhibitors: 9 achieved complete response, 1 partial, and 2 none, with no subsequent strokes. Arab patients more often presented with fever, red cell aplasia, cytopenias, and immunodeficiency at younger ages. Three patients underwent hematopoietic stem cell transplantation (HSCT). Two responded favorably, one died of infection-related complications after engraftment.

Conclusions: We observed a distinct, ethnicity-driven genotype–phenotype correlation: Georgian Jewish patients with homozygous p.Gly47Arg had a pure vasculitic/inflammatory phenotype responsive to TNF-α inhibitors, whereas Arab patients harbored heterogeneous variants with hematologic/ immune deficiency phenotype potentially benefiting from HSCT. Early, genetically informed diagnosis and phenotype-driven, multidisciplinary management are essential to improve outcomes.

Background: With regard to ethnic predilections for Gaucher disease, the most common storage disorder, Ashkenazi Jews are at risk for the non-neuronopathic form (type I), Norbottnian Swedes are at risk for the sub-acute neuronopathic form (type III), and perhaps Arabs are at risk for the very rare cardiac variant of the sub-acute neuronopathic form (type IIIc) for which there is a relatively tight genotype-phenotype correlation. Type II, the acute infantile form, being the rarest form, has not been associated with any ethnic predilection.

Objectives: To examine whether Arab ethnicity influences the Gaucher phenotype.

Methods: We reviewed the records of all Arab patients in a referral clinic of 586 patients in Israel.

Results: There were 46 patients (7.8%) of Arab ethnicity: 23 (50%) had type I disease, 16 (34.8%) had type IIIc disease, 4 (8.7%) had type IIIb disease, and 3 (6.5%) had type II disease. Type IIIc disease was characterized by genotype-phenotype correlation with homozygosity for the D409H (1342C) mutation. All five Bedouin patients (10.9%) had the R48W (C259T) mutation on at least one allele.

Conclusions: For all genotypes, disease severity among Arab patients was relatively similar to that reported among other Caucasian patients. Apparently Arab ethnicity does not impact phenotypic expression in Gaucher disease in a unique manner. The predilection for type IIIc may be a result of consanguinity.