Smith-Lemli-Opitz syndrome: how the disease is manifested?
Pregnancy is a delicate period for the couple, which often addresses a thousand doubts and uncertainties, especially as regards the health conditions of the unborn child. To have concrete answers on the risk of transmission of recessive genetic diseases to their children (such as the Smith-Lemli-Opitz syndrome, Also known as a SLO), it is possible to perform a preconception test even before the onset of pregnancy.
Slo is a genetic disease that was described for the first time in 1964
Slo is a genetic disease that was described for the first time in 1964, by the doctors Smith, Lemli and Opitz, to whom it also owes name 1 . It is a hereditary pathology that is transmitted by way autosomal recessive: having an altered copy of the gene does not produce the symptoms, but if copies are inherited two, the disease occurs. The SLO is widespread especially in the North and in the center of Europe, moreover, since the incidence rate is 1 case every 20.000/40.000, is defined rare pathology 2 .
The child shows the signs of the disease at birth, usually, but the Slo can present itself, in less serious form, even in childhood or in adulthood. It is a metabolic pathology in which the cholesterol is synthesized in smaller quantities, And it originated from an ’ Dhcr7, Responsible for reduced production of the 7DHC-Ratittase enzyme. This enzyme converts the 7-dehydrocolesterol (7DHC) in cholesterol. The subjects with the Smith-Lemli-Opitz syndrome have lower cholesterol values of cholesterol, while higher 7DHC (precursor of cholesterol). Cholesterol has both a biological role and a structural role: it is an element of cell membranes, including also myelin sheath, and deals with the synthesis of vitamin D, testosterone and cortisol (steroid hormones), and bile acids 1 .
It is possible to group the symptoms of the SLO in physicists and behavioral
From a physical point of view, the child suffering from Smith-Lemli-Opitz syndrome could have: slowed development, face malformations (palatoschisi or bifidal uvula, nostrils facing forward, small chin), microcephaly, union of the fingers of the foot (second and third finger), cryptorchidism. From a behavioral point of view, the child could show hyperactivity, sleep disorders, self -harm, autistic attitudes 2.3 . In patients with a very serious shape of Slo, malformations on the brain, cardiac, pulmonary and gastrointestinal plane may also arise 1 . The life expectancy depends on how serious the symptoms are, however many Slo patients survive up to adulthood 2 .
To diagnose the SLO, the 7DHC levels in serum and fabrics, And confirmation is obtained with themolecular analysis 1,2,3 . The therapy for SLO involves a cholesterol supplement through the intake of foods that contain large quantities of it, such as egg yolk. However, this does not counteract the accumulation of 7DHC. 1.2 . In addition, cholesterol does not pass through the blood-brain barrier and for this reason a combination therapy is being studiedsimvastatin and cholesterol supplementation, which, in addition to reaching the CNS, prevents an excessive accumulation of 7DHC 1,2 .
THE preconception genetic testing help couples to know their reproductive risk
Given the large number of existing genetic pathologies potentially transmissible to the unborn child, it is recommended to perform a pre-conception test before pregnancy. The preconception test Igea It allows you to know the risk of future parents to transmit any recessive genetic pathologies such as Slo syndrome to your children.
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