Later, Yamamotos group showed the precise glycosyl transferase set that confers the A, B and O epitopes. Genetics
Blood groups are inherited from both parents. The ABO blood type is controlled by a single gene (the ABO gene) with three types of alleles inferred from classical genetics: i, IA, and IB. The I designation stands for isoagglutinogen, another term for antigen. The gene encodes a glycosyltransferase—that is, an enzyme that modifies the carbohydrate content of the red blood cell antigens. The gene is located on the long arm of the ninth chromosome (9q34).The IA allele gives type A, IB gives type B, and i gives type O. As both IA and IB are dominant over i, only ii people have type O blood. Individuals with IAIA or IAi have type A blood, and individuals with IBIB or IBi have type B. IAIB people have both phenotypes, because A and B express a special dominance relationship: codominance, which means that type A and B parents can have an AB child. A couple with type A and type B can also have a type O child if they are both heterozygous (IBi,IAi). The cis-AB phenotype has a single enzyme that creates both A and B antigens. The resulting red blood cells do not usually express A or B antigen at the same level that would be expected on common group A1 or B red blood cells, which can help solve the problem of an apparently genetically impossible blood group.
Medical professionals have suggested that the term sebaceous cyst be avoided since it can be misleading. : 31  In practice, however, the term is still often used for epidermoid and pilar cysts. Additional images
See also
Intracranial epidermoid cyst
List of cutaneous neoplasms associated with systemic syndromes
Proliferating epidermoid cyst
Verrucous cyst

References
External links

DermNet lesions/cysts