Ultra‐rare multiple sulfatase deficiency (MSD; OMIM #272200) is caused by pathogenic variants in SUMF1. 1, 2, 3, 4, 5SUMF1 encodes formylglycine‐generating enzyme (FGE) (EC 1.8.3.7), which is essential for sulfatase activation.6 This evidence concerns the gene SUMF1 and Multiple sulfatase deficiency.