Agenesis, sacral

Failure of formation of all or part of the sacrum (the lowest section of the spine).

</P> Currarino syndrome is a condition characterized by the combination of:</P> > >Partial absence of the sacrum (the lowest portion of spine), >Anorectal (anal and rectal) abnormalities, and >An abnormal mass in front of the sacrum (due to a meningocoele or teratoma).

</LI></UL> The malformations in Currarino syndrome are all in tissues that have their embryological origin in the tail bud and may reflect disturbances in its formation during early embryonic life.

A mutation (change) in a gene called the HLXB9 homeobox gene has been identified as responsible for autosomal dominant Currarino syndrome, also known as hereditary sacral agenesis.