It is most useful as a secondary test after initial diagnosis by methylation analysis, to determine the causative mechanism. Williams syndrome is a developmental disorder that usually includes unusual facies, vascular disease, mental retardation, and specific neurobehavioral traits. It usually occurs sporadically. This disorder has been called the Elfin Face syndrome. It is caused by deletion of 4p.
Highest priority is given to the rapid turnaround of fetal and neonatal blood .
Use a tube no larger than the specimen volume, to achieve the correct ratio of heparin to blood. Note that GIVF does not set aside fetal blood for hemoglobin analysis. For fetal blood with a female karyotype, we cannot verify fetal origin. Standard harvesting takes place after 64-72 hours of culture. In addition, if at least 1 cc of blood is provided on neonates, extra cultures for 48-hour harvests will be set.