Smith Lemli Opitz Syndrome

Also known as

  • SLOS
  • 7-dehydrocholesterol reductase deficiency

Slos is an inborn error of cholesterol synthesis, it is an autosomal recessive, multiple malformation syndrome caused by a mutation in the enzyme 7 dehydrocholesterol reductase or DHCR7. It causes a broad spectrum of effects, ranging from mild intellectual disability and behavioural problems to lethal malformations.

Condition details

Physical Characteristics can include; low-set and posteriorly rotated ears, high-arched, narrow, hard palate, cleft lip/palate, agenesis or hypoplasia of the corpus callosum, cerebellar hypoplasia, increased ventricular size, decreased frontal lobe size, polydactyly of hands or feet, short, proximally placed thumb, other finger malformations, syndactyly of second and third toes, ambiguous or female-like male genitalia, congenital heart defects, renal, pulmonary, liver and eye abnormalities. Currently, the most common form of treatment for SLOS involves dietary cholesterol supplementation. Anecdotal reports indicate that this has some benefits; it may result in increased growth, lower irritability, improved sociability, less self-injurious behaviour, less tactile defensiveness, fewer infections, more muscle tone, less photosensitivity and fewer autistic behaviours.

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Photos of affected individuals

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  • Baby imageBaby
  • No toddler imageToddler
  • No child 4-10 imageChild 4-10
  • No child 10-18 imageChild 10-18
  • No adult imageAdult

Typical age range of first manifestation

  • Can manifest in Baby
  • Can manifest in Toddler
  • Can manifest in Child 4-10
  • Can manifest in Child 10-18
  • Does not manifest in Adult


Affected genes identified to date

Inheritance patterns

Is Autosomal recessive

Are carriers affected?

How many are affected?

Support groups and organisations

No groups found

Known experts

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