Deficiency of adenosine deaminase 2: a case series revealing clinical manifestations, genotypes and treatment outcomes from Turkey

A wide spectrum of phenotype of deficiency of deaminase 2 (DADA2): a systematic literature review

INTRODUCTION

Deficiency of adenosine deaminase 2 (DADA2) is a rare monogenic autoinflammatory disease, whose clinical phenotype was expanded since the first cases, originally described as mimicker of polyarteritis nodosa, with immunodeficiency and early-onset stroke.

METHODS

A systematic review according to PRISMA approach, including all articles published before the 31st of August 2021 in Pubmed and EMBASE database was performed.

RESULTS

The search identified 90 publications describing 378 unique patients (55.8% male). To date 95unique mutations have been reported. The mean age at disease onset was 92.15 months (range 0-720 months), 32 (8.5%) showed an onset of the first signs/symptoms after 18 years old and 96 (25.4%) after 10 years old. The most frequent clinical characteristics described were cutaneous (67.9%), haematological manifestations (56.3%), recurrent fever (51.3%), neurological as stroke and polyneuropathy (51%), immunological abnormalities (42.3%), arthralgia/arthritis (35.4%), splenomegaly (30.6%), abdominal involvement (29.8%), hepatomegaly (23.5%), recurrent infections (18.5%), myalgia (17.9%), kidney involvement (17.7%) etc. Patients with skin manifestations were older than the others (101.1 months SD ± 116.5, vs. 75.3 SD ± 88.2, p 0.041), while those with a haematological involvement (64.1 months SD ± 75.6 vs. 133.1 SD ± 133.1, p < 0.001) and immunological involvement (73.03 months SD ± 96.9 vs. 103.2 SD ± 112.9, p 0.05) are younger than the others. We observed different correlations among the different clinical manifestations. The use of anti-TNFα and hematopoietic cell stems transplantation (HCST) has improved the current history of the disease.

CONCLUSION

Due to this highly variable phenotype and age of presentation, patients with DADA2 may present to several type of specialists. Given the important morbidity and mortality, early diagnosis and treatment are mandatory.

Diagnosis and management of adenosine deaminase 2 deficiency children: the experience from China

BACKGROUND

Deficiency of adenosine deaminase 2 (DADA2) is a rare autoinflammatory disease caused by mutations in the ADA2 gene. Few Chinese cases have been reported. We describe and compare the clinical features, genotypes, and treatments of Chinese DADA2 patients and non-Chinese patients.

METHODS

Primary immunodeficiency disease panel or whole-exome sequencing was performed for suspected cases, and assays for adenosine deaminase 2 (ADA2) enzyme activity were also carried out for the patients and their parents. Case reports of Chinese and non-Chinese patients with DADA2 were searched in PubMed and Chinese national databases.

RESULTS

Seven unrelated children from China with DADA2 were included in our study. Five were identified at Peking Union Medical College Hospital, and two had been reported previously (1 on PubMed and 1 in Chinese literature). Fourteen mutations in ADA2 were identified, 7 of which have not previously been reported in non-Chinese patients. Four children who underwent enzymatic analysis had lower ADA2 activity compared with their parents. Phenotypic manifestations included fever, skin symptoms, vasculitis, and neurologic involvement. Treatments varying from steroids, immunosuppressants, and tocilizumab, anti-TNF therapy and hematopoietic stem cell transplantation (HSCT) were effective depending on phenotype and severity.

CONCLUSION

This study includes the largest number of Chinese DADA2 patients to date. We recommend the combination of enzymatic analysis with gene screening to confirm the diagnosis. Different genotypes were observed among Chinese DADA2 patients; most phenotypes were similar to those of non-Chinese DADA2 patients, except for growth retardation. Disease remission might not be achieved with anti-IL-6 therapy.

The Many Faces of a Monogenic Autoinflammatory Disease: Adenosine Deaminase 2 Deficiency

PURPOSE OF REVIEW

We aim to describe the pathophysiology, clinical findings, diagnosis, and treatment of deficiency of adenosine deaminase 2 (DADA2).

RECENT FINDINGS

DADA2 is a multi-organ disease of children and less often adults, which can present with wide-ranging manifestations including strokes, medium vessel vasculitis, hematologic disease, and immunodeficiency. Diagnosis is through detection of reduced activity level of the adenosine deaminase 2 (ADA2) enzyme and/or identification of bi-allelic mutations in the ADA2 gene. Outside of high-dose glucocorticoids, conventional immunosuppression has been largely ineffective in treating this relapsing and remitting disease. Vasculitic-predominant manifestations respond extremely well to tumor necrosis factor-α inhibition. Hematopoietic stem cell transplantation can lead to normalization of enzyme activity, as well as resolution of vasculitic, hematologic, and immunologic manifestations, although treatment-related adverse effects are not uncommon. Early detection of this disease across multiple disciplines could prevent devastating clinical outcomes, especially in genetically pre-disposed populations.