Biallelic variants in SLC5A7 underlie congenital myasthenic syndrome 20 (MIM #617143) characterized by muscular hypotonia and weakness, ptosis, poor sucking, and swallowing and prominent episodic apnea with a neonatal onset.12 Severity can vary, and acetylcholine esterase inhibitors show good results in some patients. This evidence concerns the gene ACHE and Congenital myasthenic syndromes.