ARSA and metachromatic leukodystrophy: To our knowledge, there have been only 3 cases of paternal UPD 22 reported (Table 1),[20–22] two of them phenotypically normal, and both of them and their father have robertsonian translocation.[20,21] The third one had metachromatic leukodystrophy,[22] which is an autosomal recessive disease caused by defects of a protein coding gene ARSA (OMIM ID: ∗607574).