Prenatal Testing for NPS

As most people with NPS probably know by now, it is an autosonal dominant condition i.e. each child of a person with NPS has a 50% chance of inheriting the syndrome irrespective of birth order or gender.
Since the gene has been mapped (we know here it is on chromosome 9) it is possible to perform pre-natal diagnosis for couples who do not wish to pass the syndrome to their children. At the moment, this diagnosis requires a chorionic villus sample (CVS) to be taken at about 10 weeks
of gestation. The CVS is made up of fetal cells. By comparing the fetal DNA with that from the parents it is possible to determine whether the fetus will inherit NPS. It is not possible to determine how severe NPS would be relative to the affected parent or other children.
Obviously, the termination of an affected fetus is not something that everybody feels comfortable with. Other concerns include having to wait until the 10th week of gestation for the CVS to be performed and then wait another week or so for the lab results. However, if couples feel that they do not wish to pass on NPS and do not object to termination, this procedure is as safe and accurate as possible.
A future option is called pre-implantation diagnosis. Once the NPS gene is identified it will be theoretically possible to determine the affected
status of the embryo at the 8-cell stage of development. The embryos would be generated by in vitro-fertilization techniques. A single cell would be removed form the embryos at the 8 cell stage and tested for the presence of the NPS mutation. Embryos not carrying the mutation would then be placed in the womb. However, THIS PROCEDURE IS CURRENTLY EXPERIMENTAL for other genetic diseases, and at the momemt and has a HIGH ERROR RATE. Insurance companies will not re-imburse for this procedure ($10 - 20,000 +).
Other possibilities include the use of sperm or egg donors (as appropriate). Obviously the child will receive no genes from the affected parent whereas using the above procedures only the mutated NPS gene is not passed on.
My lab DOES NOT perform either of the tests described above. However, I will consult with other diagnostic labs anywhere in the world to facilitate diagnosis. If you have any questions feel free to call me toll free at 1-800-211-4975 (Mon - Fri, 9am - 5:30pm Eastern) or 1-410-955-7948 (if calling from outside USA). Please understand that I am not a physician or a genetic counsellor but will do my best to explain the testing procedure. In most cases I should be able to give you the name of genetic counsellor near you.
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Iain McIntosh, PhD.
Center for Medical Genetics
Johns Hopkins University School of Medicine
600 North Wolfe Street / Blalock 1012G
Baltimore, MD 21287-4922
phone 410-955 7948
fax 410-614 2522