This diagnostic challenge is not unique to GA1; other metabolic diseases, such as MTP or LCHAD deficiencies, congenital adrenal hyperplasia (CAH), and carnitine palmitoyltransferase-II (CPT-II) deficiency, have also been missed on NBS [5,18-21], underscoring the need for more comprehensive diagnostic approaches. This evidence concerns the gene HADHA and congenital adrenal hyperplasia.