Congenital methemoglobinemia type II in a 5‐year‐old boy.

Key Clinical Message: Congenital Methemoglobinemia is a rare neurologic condition which can mimic other diseases such as epilepsy syndromes and leukodystrophies. The responsible gene, <italic>CYB5R3</italic>, is not typically included on commonly order neurologic and epilepsy panels. We recommend that laboratories include this gene on these tests which often precede larger‐scale genetic studies. [ABSTRACT FROM AUTHOR]