However, type IV represents a confusing and ever-growing subgroup encompassing all “unclassified” symptoms (2, 5), which includes MEDGEL syndrome, characterized by 3-MGA-uria, dystonia-deafness, encephalopathy, and Leigh-like syndrome (MEGDEL, OMIM ID: 614739), known to be caused by serine active site containing 1 (SERAC1) variants. This evidence concerns the gene SERAC1 and deafness.