Smith-Lemli-Opitz syndrome
Updates to Article Attributes
Smith Lemli Opitz syndrome (SLOS) also known as 7-dehydrocholesterol reductase deficiency is a congenital developmental disorderan inborn error of cholesterol synthesis.
Epidemiology
The estimated incidence is at 1:20000-40000 live births. Prevalence may be greater in Nordic countries.
Pathology
The condition often results from a mutation in the DHCR7 gene on chromosome 11q12-13 which reduces activity of 7-dehydrocholesterol reductase. Rarely there may be a mutation in chromosome 7q32.1. There is then a lack of cholesterol production as well as build up of potentially toxic by-products of cholesterol production which accumulate in the blood and other tissues. It was traditionally classified into 2 types although they are not considered to represent the spaectrumis differeringspectrum differing severity.
Genetics
It carries an autosomal recessive inheritance 5 .
Associations
Markers
- low maternal low oestriol 4 : although non specific
Clinical features
There are many which include:
- CNS
- mental retardation
- hyperexitability
- microcephaly
- hypotonia
- cranio-facial
- limb
- post axial polydactyly
- syndactyly: usually 2nd and 3rd toes
- congenital cardiac anomalies
- congenital urogenital anomalies
- intra-uterine growth restriction (IUGR)
Radiographic features
Antenatal ultrasound
There may be increased nuchal translucency in 1st trimester as an early feature 3. Antenatal ultrasound may also be able to detect some of the above clinical features.
Prognosis
The syndrome carries a poor prognosis with most infants not surviving soon after birth.
-<p><strong>Smith Lemli Opitz syndrome (SLOS)</strong> also known as <strong>7-dehydrocholesterol reductase deficiency</strong> is a congenital developmental disorder.</p><h4>Epidemiology</h4><p>The estimated incidence is at 1:20000-40000 live births. Prevalence may be greater in Nordic countries.</p><h4>Pathology</h4><p>The condition often results from a mutation in the DHCR7 gene on chromosome 11q12-13 which reduces activity of 7-dehydrocholesterol reductase. Rarely there may be a mutation in chromosome 7q32.1. There is then a lack of cholesterol production as well as build up of potentially toxic by-products of cholesterol production which accumulate in the blood and other tissues. It was traditionally classified into 2 types although they are not considered to represent the spaectrumis differering severity.</p><h5>Genetics</h5><p>It carries an autosomal recessive inheritance <sup>5</sup> .</p><h5>Associations</h5><ul><li><a href="/articles/hirschsprung-disease">Hirschsprung disease</a></li></ul><h5>Markers</h5><ul><li>low maternal low oestriol <sup>4</sup> : although non specific</li></ul><h4>Clinical features</h4><p>There are many which include:</p><ul>- +<p><strong>Smith Lemli Opitz syndrome (SLOS)</strong> also known as <strong>7-dehydrocholesterol reductase deficiency</strong> is an inborn error of cholesterol synthesis. </p><h4>Epidemiology</h4><p>The estimated incidence is at 1:20000-40000 live births. Prevalence may be greater in Nordic countries.</p><h4>Pathology</h4><p>The condition often results from a mutation in the DHCR7 gene on chromosome 11q12-13 which reduces activity of 7-dehydrocholesterol reductase. Rarely there may be a mutation in chromosome 7q32.1. There is then a lack of cholesterol production as well as build up of potentially toxic by-products of cholesterol production which accumulate in the blood and other tissues. It was traditionally classified into 2 types although they are not considered to represent the spectrum differing severity.</p><h5>Genetics</h5><p>It carries an autosomal recessive inheritance <sup>5</sup> .</p><h5>Associations</h5><ul><li><a href="/articles/hirschsprung-disease">Hirschsprung disease</a></li></ul><h5>Markers</h5><ul><li>low maternal low oestriol <sup>4</sup> : although non specific</li></ul><h4>Clinical features</h4><p>There are many which include:</p><ul>