Noonan Syndrome (Exons 3-4-7-8-9-13-14) Prenatal (Including Maternal Contamination)
Definition
This test covers sequence analysis, in a prenatal sample, of the exons of the PTPN11 gene most commonly associated with Noonan syndrome; the most common indications are increased nuchal thickness, cystic hygroma, hydrops, and congenital heart anomalies. Since mixing of fetal DNA with maternal cells can lead to inaccurate results, a concurrent maternal cell contamination investigation is performed to ensure the reliability of the test result; PTPN11 variants are responsible for ~50% of Noonan syndrome cases.
Gene/region examined
PTPN11 - Exon 3, PTPN11 - Exon 4, PTPN11 - Exon 7, PTPN11 - Exon 8, PTPN11 - Exon 9, PTPN11 - Exon 13, PTPN11 - Exon 14
Method
Sequence analysis
Accepted sample types
EDTA blood+, AF, CVS
Inheritance
Hereditary (a germline variant is investigated in the fetus), autosomal dominant inheritance pattern; maternal contamination control is a technical quality assurance step.