Smith Lemli Opitz Syndrome: Causes, Symptoms, Treatment

What Is Smith Lemli Opitz Syndrome?

Smith-Lemli-Opitz Syndrome is a genetic condition characterized by slown development of the fetus which continues even after birth with the child being very slow to attain the milestones. Additionally, children with Smith-Lemli-Opitz Syndrome tend to have distinctly small head, a condition called microcephaly, apart from psychomotor and mental retardation which may be variable and differ from individual to individual.

Smith-Lemli-Opitz Syndrome also causes an individual to have distinct facial features and a cleft palate. They also tend to have certain cardiac defects as well. Certain musculoskeletal abnormalities are also present in individuals with Smith-Lemli-Opitz Syndrome like fused second and third toes, presence of extra fingers and toes, and most significantly underdeveloped external genitalia in males with Smith-Lemli-Opitz Syndrome.

The severity of Smith-Lemli-Opitz Syndrome is quite variable and symptoms may differ even in affected individual of the same family. In some cases, the symptoms of Smith-Lemli-Opitz Syndrome may be so mild so as not to affect the development of the individual but in some cases it may be so severe that the affected individual may be virtually dependent on others to complete tasks.

What Is Smith Lemli Opitz Syndrome?

The main cause of Smith-Lemli-Opitz Syndrome is deficiency of enzyme 7-dehydrocholesterol reductase which facilitates cholesterol metabolism. This condition follows an autosomal recessive trait meaning that two copies of the defective gene from each parent are required for a child to develop Smith-Lemli-Opitz Syndrome.

What Are The Causes Of Smith Lemli Opitz Syndrome?

As stated, the root cause of Smith-Lemli-Opitz Syndrome is mutation of the DHCR7 gene which results in deficiency of 7-dehydrocholesterol reductase enzyme.

The function of this enzyme is to facilitate metabolism of cholesterol. This condition follows an autosomal recessive pattern meaning that two copies of the faulty gene are required from each parent for development of Smith-Lemli-Opitz Syndrome.

In case if an individual receives only one defective gene then he or she will be a carrier of the disease and will not show any symptoms whatsoever of Smith-Lemli-Opitz Syndrome.

What Are The Symptoms Of Smith Lemli Opitz Syndrome?

The symptoms of Smith-Lemli-Opitz Syndrome are variable and differ from patient to patient. Some patient may experience very mild symptoms which may not affect his or her development whereas some patients may experience severe symptoms which may make them severely disabled. Some of the symptoms of Smith-Lemli-Opitz Syndrome are:

  • Developmental delays
  • Psychomotor retardation
  • Mental retardation
  • Musculoskeletal deformities to include extra fingers or toes or a fused finger or toes
  • Cleft palate
  • Underdeveloped external genitalis, only in males
  • Ptosis of the eyes
  • Wrinkles of the skin of the upper and lower eyelids
  • Small jaw
  • Large ears
  • Vision problems in the form of cataracts
  • Neurological problems to include seizures
  • Hypotonia
  • Bowel obstruction
  • Photosensitivity

How Is Smith Lemli Opitz Syndrome Diagnosed?

In order to diagnose Smith-Lemli-Opitz Syndrome, the physician will first take a detailed history of the patient to include a family history to determine whether there are any other members in the family who have similar symptoms.

When a genetic condition like Smith-Lemli-Opitz Syndrome is suspected then an enzyme assay will be done which will clearly show deficiency 7-dehydrocholesterol reductase enzyme which will further pinpoint the diagnosis. A genetic study may also be done which will show mutation of the DHCR7 gene which will confirm the diagnosis of Smith-Lemli-Opitz Syndrome.

How Is Smith Lemli Opitz Syndrome Treated?

There is no specific treatment for Smith-Lemli-Opitz Syndrome and treatment is mainly aimed at improving symptoms and correcting any defects that may be arising out of this disorder so as to improve the quality of life of the patient.

For that, the patient will be evaluated closely by a team of specialist spanning almost all the specialties who will monitor the patient for cardiac, ocular, neurological, neuromuscular, gastrointestinal and genitourinary defects and formulate a treatment plan accordingly.

Surgery may be recommended for correction of cleft palate or fusing of the toes and fingers to correct them. Certain cardiac defects may also be corrected with surgery. The genital abnormality in males with Smith-Lemli-Opitz Syndrome also requires surgery for correction.

In some cases cholesterol supplementation may be recommended to improve the growth of the patient and improve the overall condition of the patient suffering from Smith-Lemli-Opitz Syndrome.

Pramod Kerkar, M.D., FFARCSI, DA
Pramod Kerkar, M.D., FFARCSI, DA
Written, Edited or Reviewed By: Pramod Kerkar, M.D., FFARCSI, DA Pain Assist Inc. This article does not provide medical advice. See disclaimer
Last Modified On:December 20, 2021

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