Diandric

Diandric is a term used in genetics and embryology to describe a triploid genome that contains two paternal (male) genomes. The word combines the prefix di- meaning two and the Greek root andros meaning male, reflecting its origin in paternal contributions to the genome. In the context of triploidy, diandric triploidy occurs when two paternal haploid sets are present alongside one maternal set, typically arising when two sperm fertilize a single egg (dispermy).

Clinically, diandric triploidy is associated with specific patterns of placental and fetal development. The condition often results in abnormal placental tissue, frequently described as resembling a partial hydatidiform mole, and is commonly linked to pregnancy loss. The fetal component, when present, is usually severely malformed or nonviable. Diandric triploidy contrasts with digynic triploidy, in which two maternal genomes accompany one paternal genome and which is typically associated with a smaller placenta and fetal growth restriction.

Determination of diandric versus digynic origin relies on molecular genetic testing that analyzes parental contributions to the triploid genome. These distinctions have implications for prognosis, counseling, and understanding the etiology of certain pregnancy losses. In literature, diandric triploidy is one of the two recognized parental-origin patterns of triploidy, the other being digynic triploidy, reflecting two paternal versus two maternal contributions to the triploid set.