MAB21L2 and arthrogryposis multiplex congenita: In humans, both monoallelic and biallelic MAB21L2 (Mab21-Like 2) coding variants have been reported in individuals with AMC with and without skeletal anomalies, with arginine 51 an apparent hotspot impacted by 5/11 reported alterations3,5–10, generally leading to a more severe phenotype of AMC and skeletal dysplasia5,6,11.