Proximal bilateral pudendal neuropathy has been demonstrated in patients with rectal prolapse who have fecal incontinence. This finding was shown to be absent in healthy subjects, and may be the cause of denervation-related atrophy of the external anal sphincter. Some authors suggest that pudendal nerve damage is the cause for pelvic floor and anal sphincter weakening, and may be the underlying cause of a spectrum of pelvic floor disorders.Sphincter function in rectal prolapse is almost always reduced. This may be the result of direct sphincter injury by chronic stretching of the prolapsing rectum. Alternatively, the intussuscepting rectum may lead to chronic stimulation of the rectoanal inhibitory reflex (RAIR - contraction of the external anal sphincter in response to stool in the rectum). The RAIR was shown to be absent or blunted. Squeeze (maximum voluntary contraction) pressures may be affected as well as the resting tone. This is most likely a denervation injury to the external anal sphincter.The assumed mechanism of fecal incontinence in rectal prolapse is by the chronic stretch and trauma to the anal sphincters and the presence of a direct conduit (the intussusceptum) connecting rectum to the external environment which is not guarded by the sphincters.The assumed mechanism of obstructed defecation is by disruption to the rectum and anal canals ability to contract and fully evacuate rectal contents.
Infantile cerebral and cerebellar atrophy with postnatal progressive microcephaly is a rare hereditary autosomal recessive malformation syndrome of the central nervous system characterized by profound motor delays and intellectual disabilities, progressive microcephaly, hypertonia, spasticity, clonus and epilepsy. MRI findings include severe cerebellar and cerebral deterioration (atrophy) and impaired myelination. This condition is an example of consequences from the Founder effect, especially that of Jewish populations.It has been described in 5 infants from 4 Israeli families of ethnic Caucasus Jewish descent. The genetic cause was found to be a homozygous mutation of the MED17 gene, located in chromosome 11, this mutation is called L371P.In vitro functional expression assays of the L371P mutation showed that it results in a functionally inactive MED17 protein. == References ==