User:Nthoman1/sandbox

Choice of Topic: Acephaly - A congenital disorder resulting in the absence of the head.

This project will be a team effort between Kristen Gibson and Natalie Thoman.

The main sandbox used will be Natalie Thoman's.

Draft Article:

Acephaly is a developmental condition characterized by the complete absence of encephalic structure (head). While the condition is usually most prominent in monozygotic twins, it has also been observed in singleton pregnancies. There are multiple mechanisms proposed to be responsible for the condition.

Most common type of acardia (add link) - conditions arising from vascular anastomoses in the placenta.

Mechanisms

Twin reversed arterial perfusion (TRAP) - Occurs in monozygotic twins - Can occur without any chromosomal abnormalities in the parents - indicating may be environmental in cause

Amniotic banding - Can cause limb amputations - Mechanical rather than genetic factors (ex. Premature amniotic rupture) - More prominent to singleton pregnancies Acephaly in Mice Acephaly in mice models can be caused by the knockout of Lim1 gene. Mize homozygous for the Lim1 knockout allele lack anterior head structure, while the rest of the body shows normal development. Lim1 is a homeobox gene expressed in the head-organizer, and has been shown to be an essential regulator of the vertebrate head organizer (Shalot and Behringer)

Citations http://www.dirjournal.org/sayilar/17/buyuk/pdf_DIR_145.pdf http://www.fetalsono.com/teachfiles/AcardAc.lasso

/Acephaly