MedGen

The Emm red blood cell antigen is assigned number 901008 in the International Society of Blood Transfusion (ISBY) 901 series of high incidence antigens. Emm has been designated the 42nd blood group system. Rare individuals have an Emm- phenotype due to homozygous loss-of-function mutations in the PIGG gene. These individuals often have naturally occurring anti-Emm antibodies that are identified during routine blood type and crossing. These antibodies have the potential to cause acute hemolytic transfusion reactions (summary by Lane et al., 2021). [from OMIM]

Neurodevelopmental disorder with or without hypotonia, seizures, and cerebellar atrophy (NEDHSCA) is an autosomal recessive disorder characterized by severely delayed psychomotor development, hypotonia apparent since infancy, and early-onset seizures in most patients. Some patients may have additional features, such as cerebellar atrophy, ataxia, and nonspecific dysmorphic features. NEDHSCA is one of a group of similar neurologic disorders resulting from biochemical defects in the glycosylphosphatidylinositol (GPI) biosynthetic pathway. Some patients with NEDHSCA may have the Emm-null blood group phenotype (see 619812) (summary by Makrythanasis et al., 2016; Duval et al., 2021). For a discussion of genetic heterogeneity of GPI biosynthesis defects, see GPIBD1 (610293). [from OMIM]