Hemoglobin Beth Israel [HBB:c.308A>G (p.Asn103Ser)]: an ultra-rare, low oxygen-affinity, non-methemoglobinemic hemoglobin diagnosed on targeted resequencing as cause of dominantly inherited benign cyanosis.

Among these, low oxygen-affinity Hb variants are a peculiar subset, displaying autosomal dominant inheritance of normocytic anemia, cyanosis, and usually inapparent hypoxemia detected by a low SpO2 on pulse oximetry. However, other abnormal Hb variants like Hb Beth Israel, Hb Kansas, and Hb Saint Mande also lead to cyanosis without overt methemoglobinemia [[2]]. We report here a family with Hb Beth Israel, a rare Hb variant with very low oxygen affinity. [Extracted from the article]