Smith-Lemli-Opitz syndrome is a rare metabolic disease in which the body does not make enough cholesterol. This rare disease develops in utero, leading to many disorders. What are the causes and symptoms of Smith-Lemli-Opitz syndrome? What is the treatment of this condition?

Smith-Lemli-Opitz Syndrome (SLOS)is a genetically determinedmetabolic disease.It is included in the group of rare diseases because it occurs at about 1: 20,000-1: 60,000 births. It is estimated that the incidence of the disease in Poland is higher than in other European countries and amounts to 1: 2,300-1: 3,937, which makes Smith-Lemli-Opitz syndrome one of the most common metabolic diseases in our country.

Smith-Lemli-Opitz syndrome: causes

The cause of the Smith-Lemli-Opitz syndrome is a mutation of the DHCR7 gene, located on the long arm of chromosome 11. This gene is responsible for the formation of the DHCR7 protein, which is involved in the biosynthesis of cholesterol. The effect of a gene mutation is that the body does not produce enough cholesterol, which is necessary for the proper development of the fetus. Cholesterol is also a building block for cell membranes and the envelope that protect nerve cells.

Smith-Lemli-Opitz syndrome is an autosomal recessive disease, which means that the gene responsible for the disease is passed on together with a recessive gene located on the autosomal (somatic) chromosome that inherits all traits except traits conjugated with sex.

Smith-Lemli-Opitz syndrome: symptoms

The symptoms of Smith-Lemli-Opitz syndrome depend on the form of the disease. In the mild form of SLOS it is observed:

  • microcephaly
  • variable muscle tension (laxity followed by stiffness)
  • disturbed growth
  • feeding problems (no sucking reflex, difficulty swallowing) and associated poor weight gain
  • facial deformity (wide-set eyes, drooping eyelids, small lower jaw, short nose, low-set ears)
  • deformations of the upper limbs, e.g. polydactyly, i.e. additional fingers on the hands and feet,syndactyly - Y-shaped fusion of the fingers of the second and third toes, flexion grooves on the palms and changes in fingerprints, short thumbs
  • underdevelopment of the genital organs: micropenis, cryptorchidism, i.e. the failure of the testes to descend into the scrotum, underdevelopment of the scrotum
  • psychomotor and intellectual development delay
  • skin blemishes

In the severe form, SLOS symptoms also include numerous congenital defects: digestive system (e.g. pyloric stenosis), blood system (e.g. atrial septal defect), kidneys (e.g. hydronephrosis), vision (e.g. anidria , i.e. the lack of the iris of the eye).

Ww. features come in various combinations and with varying intensity.

Smith-Lemli-Opitz syndrome: diagnosis

Diagnosis is made on the basis of physical examination and laboratory tests (people with SLOS can be determined to have low blood cholesterol and high levels of 7-dehydrocholesterol).

If a woman has already given birth to a child with SLOS, her doctor should refer her to prenatal testing: invasive tests such as amniocentesis, chorionic villus sampling to look for known mutations in the fetus previously diagnosed in the carrier parents, or non-invasive screening.

Smith-Lemli-Opitz syndrome: treatment

Smith-Lemli-Opitz syndrome is an incurable disease. Treatment aimed at alleviating the symptoms of the disease and improving the quality of life mainly consists of rehabilitation. A very important element of it is the exercise of the muscles responsible for chewing, because people suffering from SLOS have problems with food intake.

Usually, you need regular care from doctors of various speci alties, such as a cardiologist, neurologist, urologist or ophthalmologist. A dermatological consultation may also be needed, as the skin of SLOS patients is photosensitive and various skin reactions may appear in the event of excessive exposure to the sun.

If necessary, coexisting disorders are treated, also surgically (e.g. in the case of hypertrophic stenosis of the pylorus).

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Smith-Lemli-Opitz syndrome: diet

A helpful form of treatment is a high-cholesterol diet, the purpose of which is to compensate for the cholesterol levels that are lowered as a result of the disease. The patient should consume about 40-150 mg / kg / day of cholesterol, but the final dose is determined by the doctor.

Category:

Genetic diseases