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Many organ systems are affected by triploidy, but the central nervous system and skeleton are the most severely affected: . Common central nervous system defects seen in triploidy include holoprosencephaly, hydrocephalus (increased amount of cerebrospinal fluid within the brain), ventriculomegaly, Arnold–Chiari malformation, agenesis of the corpus callosum and neural tube defects.
The CDC and National Birth Defect Project studied the incidence of birth defects in the US. Key findings include: [ citation needed ] Down syndrome was the most common condition with an estimated prevalence of 14.47 per 10,000 live births, implying about 6,000 diagnoses each year.
The twin reversed arterial perfusion, or T.R.A.P. sequence, results in an 'acardiac twin', a parasitic twin that fails to develop a head, arms and a heart.The parasitic twin, little more than a torso with or without legs, receives its blood supply from the host twin by means of an umbilical cord-like structure, much like a fetus in fetu, except the acardiac twin is outside the autosite's body.
Fetus in fetu may be a parasitic twin fetus growing within its host twin. Very early in a monozygotic twin pregnancy, in which both fetuses share a common placenta, one fetus wraps around and envelops the other. The enveloped twin becomes a parasite, in that its survival depends on the survival of the host twin, by drawing on the host twin's ...
Heart disorders (Congenital heart defects) Hemifacial microsomia; Holoprosencephaly; Huntington's disease; Hirschsprung's disease, or congenital aganglionic megacolon; Hypertrichosis; Hypoglossia; Hypomelanism or hypomelanosis (albinism) Hypospadias; Haemophilia; Heterochromia; Hemochromatosis
Most congenital heart defects are not associated with other diseases. [3] A complication of CHD is heart failure. [2] Congenital heart defects are the most common birth defect. [3] [11] In 2015, they were present in 48.9 million people globally. [8] They affect between 4 and 75 per 1,000 live births, depending upon how they are diagnosed.
Research has shown the lack of folic acid (folate) is a contributing factor in the pathogenesis of neural tube defects, including spina bifida. Supplementation of the mother's diet with folate can reduce the incidence of neural tube defects by about 70%, and can also decrease the severity of these defects when they occur.
The presence of a "T-sign" at the inter-twin membrane-placental junction is indicative of monochorionic-diamniotic twins (that is, the junction between the inter-twin membrane and the external rim forms a right angle), whereas dichorionic twins present with a "lambda (λ) sign" (that is, the chorion forms a wedge-shaped protrusion into the ...