LRP2 and Donnai-Barrow syndrome: However, apart from BDA who was found to carry biallelic pathogenic variants in the LRP2 gene and, for this reason, and after a careful clinical revaluation, was assessed to suffer from an atypical form of DB/FOAR syndrome [64], the other patient (AMS) did not suffer from cystinuria, despite carrying biallelic variants in the SLC3A1 gene that were classified as likely pathogenic according to ACMG/AMP variant interpretation.