Pregnancy Information
SLOS is caused by receiving two mutated genes that are related to cholesterol synthesis; one from each parent. Each parent of an SLO child is a carrier and thus has one good gene and one mutated gene, and therefore there is a 25% chance of having a child with SLO based on the following combination's:
- Mother's good gene and father's good gene (unaffected child)
- Mother's good gene and father's mutated gene (unaffected child, but a carrier)
- Mother's mutated gene and father's good gene (unaffected child, but a carrier)
- Mother's mutated gene and father's mutated gene (child has SLO)
That, of course, means that there is a 75% chance of having a non-affected child. The non-affected child however may be a carrier.
Post conception testing includes Chorionic Villus Sampling (CVS) and Amniocentisis. In each of these tests, it is the cholesterol levels that are checked (sterol cholesterol and 7-DHC) to determine if the fetus has SLOS. Both tests can be done as early as 9-10 weeks, but should be done with a very reputable source.
A urine test has also been devised, but it's accuracy is still being investigated, and it cannot determine if the fetus is a carrier.
Pre-conception testing can be done two ways. The first way is to take the female's eggs and test the polar body of the egg. If the polar body is determined to have the mutated gene causing SLOS, then the egg itself does not have those mutated genes. This, of course does not guarantee that the child would not be a carrier. The second way is to test by way of In-Vitro Fertilization and Pre-implantation Genetic Diagnosis (PGD). The basic procedure for this is to create embryos from the female's eggs and the male's sperm and then take a piece of the embryo for testing once the embryo reaches the 8 cell stage. Before the IVF cycle is started, the testing lab must create a test specific to the couple's DNA. It is important to note that the testing should be done by a lab that deals in molecular biology, and that knowing the gene mutations carried by the parents is best for accurate testing. Cost and insurance coverage varies by state for IVF and typically the specific genetic test for SLO is not covered.
Some families have looked into the avenue of PGD and have forwarded this information:
Dr. Mark Hughes is a leading researcher in the field of PGD and is the best contact for this procedure. He works out of Wayne University in Detroit, Michigan. Be advised that the timeframes that are quoted are typically grossly misunderstated (8-12 months instead of 6 weeks).
Reproductive Genetics Intitute
Chicago, IL
773/296-7095 Christina Masciangelo was last known contact
Other concerns that have come up in pregnancies are low estriol levels, low progesterone levels, and slow growth of the fetus. In many cases, the head, upper arms and upper legs are smaller than other measurements.
It has been determined that doctors can now use the triple screen or AFP test as a red flag for potential SLOS.
As well, the doctors now feel (although not proven), that cholesterol will transfer from mom to baby via placenta for the first and second trimester, the most critical time of development. Breast milk cholesterol seems to pass through the blood brain barrier.
