PT  - JOURNAL ARTICLE
AU  - Seza Özen
AU  - Ezgi Deniz Batu
AU  - Ekim Z. Taşkıran
AU  - Hatice Asuman Özkara
AU  - Şule Ünal
AU  - Naz Güleray
AU  - Abdulsamet Erden
AU  - Ömer Karadağ
AU  - Fatma Gümrük
AU  - Mualla Çetin
AU  - Hafize Emine Sönmez
AU  - Yelda Bilginer
AU  - Deniz Çağdaş Ayvaz
AU  - Ilhan Tezcan
TI  - A Monogenic Disease with a Variety of Phenotypes: Deficiency of Adenosine Deaminase 2
AID  - 10.3899/jrheum.181384
DP  - 2020 Jan 01
TA  - The Journal of Rheumatology
PG  - 117--125
VI  - 47
IP  - 1
4099  - http://www.jrheum.org/content/47/1/117.short
4100  - http://www.jrheum.org/content/47/1/117.full
SO  - J Rheumatol2020 Jan 01; 47
AB  - Objective. Deficiency of adenosine deaminase 2 (DADA2) is an autosomal recessive autoinflammatory disorder associated with ADA2 mutations. We aimed to investigate the characteristics and ADA2 enzyme activities of patients with DADA2 compared to non-DADA2 patients.Methods. This is a descriptive study of 24 patients with DADA2 who were admitted to the Adult and Pediatric Rheumatology, Pediatric Haematology, and Pediatric Immunology Departments of Hacettepe University. All ADA2 exons were screened by Sanger sequencing. Serum ADA2 enzyme activity was measured by modified spectrophotometric method.Results. Twenty-four patients with DADA2 were included: 14 with polyarteritis nodosa (PAN)-like phenotype (Group 1); 9 with Diamond-Blackfan anemia (DBA)-like features, and 1 with immunodeficiency (Group 2). Fourteen PAN-like DADA2 patients did not have the typical thrombocytosis seen in classic PAN. Inflammatory attacks were evident only in Group 1 patients. Serum ADA2 activity was low in all patients with DADA2 except one, who was tested after hematopoietic stem cell transplantation. There was no significant difference in ADA2 activities between PAN-like and DBA-like patients. In DADA2 patients with one ADA2 mutation, serum ADA2 activities were as low as those of patients with homozygote DADA2. ADA2 activities were normal in non-DADA2 patients. ADA2 mutations were affecting the dimerization domain in Group 1 patients and the catalytic domain in Group 2 patients.Conclusion. We suggest assessing ADA2 activity along with genetic analysis because there are patients with one ADA2 mutation and absent enzyme activity. Our data suggest a possible genotype–phenotype correlation in which dimerization domain mutations are associated with PAN-like phenotype, and catalytic domain mutations are associated with hematological manifestations.