Twins who develop from a single fertilized ovum; identical twins. Often referred to as MZ twins, in contrast to DZ twins (dizygotic twins).
Twins developing from a single fertilized egg that splits in half at an early stage of cleavage and develops into two complete fetuses. Monozygotic twins are always of the same sex, have the same genetic makeup, and closely resemble each other in all characteristics. About one- third of all twins are monozygous; such twinning is not hereditary and occurs in all races. Also called identical twins.
Twins who develop from a single ovum fertilized by a single spermatozoon. Also known as identical or uniovular twins.
Twins that develop from a single fertilized ovum.- Monozygotic twins have the same genetic makeup and, consequently, are of the same gender and strikingly resemble each other physically, physiologically, and mentally. They develop within a common chorionic sac and have a common placenta. Each usually develops its own amnion and umbilical cord. Such twins may result from development of two inner cell masses within a blastocyst, development of two embryonic axes on a single blastoderm, or the division of a single embryonic axis into two centers.
Also known as identical twins, two babies that come from a single fertilized egg and share identical genetic makeup. If one monozygotic twin develops MS, the other has a 30/100 risk of developing the disease, indicating that factors other than genetic makeup contribute to the etiology of MS.