Evaluation of Patients with Severe Combined Immunodeficiency Due to Adenosine Deaminase Deficiency: A Single-Center Experience

Objective: This study aimed to evaluate the clinical, immunological, and prognostic features of seven patients diagnosed with Adenosine Deaminase Deficiency Severe Combined Immunodeficiency (ADA-SCID) at Marmara University. The aim of this study was to enhance the recognition and management of this condition, which is characterized by impaired lymphocyte development and early severe infections. Methods: This retrospective study included seven patients with ADA-SCIDs who were monitored from 2012 to 2024. Patient data, including demographics, clinical findings, laboratory results, and imaging, were retrieved from hospital records. Diagnostic criteria focused on ADA enzyme activity and genetic mutations. Treatment regimens, such as immunoglobulin replacement, antimicrobial prophylaxis, enzyme replacement therapy, and hematopoietic stem cell transplantation (HSCT), were documented. Statistical analyses were performed using descriptive methods. Results: The cohort (6 males, 1 female) presented a median age at diagnosis of 3 months. Consanguinity was observed in 86% of cases. Key symptoms included lymphopenia, recurrent infections, thymus absence, and systemic manifestations. Six patients received HSCT, and two underwent matched donor transplantation. One patient received gene therapy because of the absence of a matched donor. Opportunistic infections were prevalent, including cytomegalovirus and recurrent skin infections noted. Overall, two patients died of post-HSCT complications. Conclusions: ADA-SCID is a life-threatening condition characterized by early severe infections and systemic manifestations. Early diagnosis and tailored treatment, including HSCT and gene therapy, are essential for improving survival outcomes. This study emphasizes the importance of early diagnosis to improve the survival and management outcomes of patients with ADA-SCID.