Conjoined Twins A
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Note what signs you see.
I (W. Wertelecki, M.D.) see conjoined twins (CTW) at the thorax (thoracopagus). Pagus is an interesting word, it may even mean your “pay” (see elaborations in Pandora Word Box). The pagus site (attachment point) is not at random, a point to keep in mind concerning the pathogenesis of CTW. Another point is that CTW are always identical (monozygotic) but discordant for malformations and are overwhelmingly females. These facts argue against a “genetic” (preconceptional) etiology (cause). However, the cause of identical twins (monozygotic) may be distinct from the cause of their becoming conjoined.
PERSPECTIVE: We noted a temporary cluster of CTW occurrences in Rivne Province of Ukraine but there was no evidence of an association with impacts of ionizing radiation nor was there a prolongation of the elevated CTW rates (Wertelecki et al. reports). CTW and in particular if conjoined represent the earliest in embryologic terms human malformations. Furthermore, MZ (monozygotic or identical) twins also represent the earliest human anomalies.