Congenital Methemoglobinemia with Multiple Limb Anomalies in an 11-Year-Old Boy

Abstract

An adolescent male presenting with multiple congenital limb defects planned for corrective surgery was incidentally detected to have low oxygen saturation on room air at rest. The child was not on any medication. After a pediatric cardiologist opinion a 2D Echocardiography and ECG were done which turned out to be normal. Proper history, detailed examination and simple bedside test carried out by the pediatricians proposed the possibility of methemoglobinemia. Since the child was not on any medication and after ruling out the possibility of toxin intake, a clinical diagnosis of congenital methemoglobinemia was arrived at, which was confirmed by the blood investigations. Since, systemic methemoglobinemia is a rare cause of cyanosis and has a varied presentation depending on the type and cause, a high index of suspicion is needed for the diagnosis. The coexistence of multiple congenital limb defects prompts one to think about a possible co-relation.

Molecular Dynamic Simulation Analysis of a Novel Missense Variant in CYB5R3 Gene in Patients with Methemoglobinemia

“…Methemoglobinemia type II (generalized) affects all tissues of the body and manifests in cyanosis as well as neurological complications [ 9 , 10 ]. Recently, congenital methemoglobinemia was also reported in a patient with multiple limb anomalies [ 11 ]. Similarly, in another study, the authors showed that loss of function mutations affecting both the FAD- and NAD-binding domains in CYB5R3 gene resulted in both type I and type II recessive congenital methemoglobinemia [ 12 ].…”