Usefulness of buccal swab sample genotyping performed at home for blood relatives of patients with alpha-1 antitrypsin deficiency

<bold>Background:</bold> Alpha-1 antitrypsin deficiency (AATD) is an underdiagnosed genetic condition which may predispose affected individuals to emphysema and liver damage. Our goal is improving diagnosis in the target population (patients with COPD or liver disease) and their relatives. In Spain, a national program for AATD diagnosis is based on genetic analysis of buccal swabs by a central laboratory (Progenika Biopharma, Vizcaya, Spain). It uses Luminex technology that simultaneously identifies the 14 most frequent deficiency variants. Recent experience has validated self-collection of buccal samples as an effective method for genotyping that is acceptable to patients. Our aim was to assess whether collection and shipment of samples by the patient's family members could extend the screening program without a visit to the doctor's office. <bold>Material and Methods:</bold> All samples from relatives (adults and children) of the index cases were reportedly collected at home from October 1, 2021 to October 1, 2023. Informed written consent was required for participation. <bold>Results:</bold> 413 samples were received (120 (29%) from children) and 374 (90.5%) samples were analyzed. The prevalence of frequent allele combinations was: 119 MM, 101 MZ, 80 MS, 29 MMmalton, 14 SZ, 11 SS, 7 MI, 6 SMmalton, 2 ZZ, 1 ZMmalton and 2 rare variants. <bold>Conclusions:</bold> In our study, referral by a family member and self-collection of samples for genotyping of potential carriers is a feasible way to avoid the need for in-office care in our clinics. This diagnostic tool can be used in adult patients or children. However, a small number of subjects (9.5%) did not respond.