Danish children with ZZ‐homozygous alpha‐1 antitrypsin deficiency are more affected on liver parameters than children with heterozygosity

Aim The longitudinal health status of Danish children with alpha‐1 antitrypsin deficiency had never previously been characterised. This study aimed to assess the changes in growth, lung and liver function through childhood in these children. Methods Danish children diagnosed between 2005 and 2020 with pathogenic variants in the Serpin family A member 1 gene were included. Retrospective data on growth, lung and liver parameters were obtained from local databases. Anthropometric Z‐scores and composite liver scores were computed. Growth and blood results were analysed using robust linear mixed models. Results The study included 184 children (68 with ZZ‐homozygosity, 116 with heterozygosity). The median follow‐up time was 7 years [IQR 3.75–9.00] for children with ZZ‐homozygosity and 0.5 years [IQR 0.0–2.0] for children with heterozygosity. Both groups had low weight‐for‐height Z‐scores at diagnosis but experienced catch‐up growth during the first year of life. In addition, children with ZZ‐homozygosity had higher serum concentrations of γ‐glutamyl transferase and alanine aminotransferase throughout childhood, when compared with children with heterozygosity. Data proved insufficient to assess lung function properly. Conclusion Children with ZZ‐homozygosity were more affected on serum liver parameters throughout childhood when compared with children with heterozygosity. Both groups experienced catch‐up growth during the first year of life.