title: Follow-up of multiple aneuploidies and single monosomies detected by noninvasive prenatal testing: implications for management and counseling.
abstract: OBJECTIVE
  To determine the underlying biological basis for noninvasive prenatal testing (NIPT) results of multiple aneuploidies or autosomal monosomies.
  
  
  METHODS
  Retrospective analysis of 113,415 tests to determine the study cohort, consisting of 138 (0.12%) cases reported as a single autosomal monosomy (n = 65), single trisomy with a sex chromosome aneuploidy (n = 36), or with multiple aneuploidies (n = 37). Clinical outcome information was reviewed and stratified into eight categories according to whether the karyotype or sonographic information agreed or disagreed with sequencing results.
  
  
  RESULTS
  Of 67 cases with fetal or neonatal karyotypes available, 16 (24%) were partially or fully concordant with the NIPT result, 4 (6%) had aneuploidy on a reference chromosome, and 47 (70%) had normal fetal chromosomes, in which 5/47 had maternal malignancies reported. One case of maternal mosaic trisomy 8 was also detected. Of cases with no fetal karyotype information, ten had an abnormal clinical outcome, one was a normal live birth, and one reported maternal malignancy.
  
  
  CONCLUSIONS
  Noninvasive prenatal test results of autosomal monosomy or multiple aneuploidies are rare but have a diversity of underlying biologic causes. Some reflect the fetal karyotype; some reflect the presence of other maternal or fetal chromosome abnormalities, and a small number are linked to maternal disease.
authors.affiliation: Illumina, Inc., Redwood City, CA, USA.
authors.forename: Holly L
authors.initials: HL
authors.lastname: Snyder
authors.affiliation: Illumina, Inc., Redwood City, CA, USA.
authors.forename: Kirsten J
authors.initials: KJ
authors.lastname: Curnow
authors.affiliation: Illumina, Inc., Redwood City, CA, USA.
authors.forename: Sucheta
authors.initials: S
authors.lastname: Bhatt
authors.affiliation: Mother Infant Research Institute, Tufts Medical Center, Boston, MA, USA.
authors.forename: Diana W
authors.identifier: http://orcid.org/0000-0001-9270-5267
authors.initials: DW
authors.lastname: Bianchi
mesh_terms: D000328:Adult; D000782:Aneuploidy; D025063:Chromosome Disorders / Q000175:diagnosis* / Q000628:therapy*; D003376:Counseling; D005260:Female; D005500:Follow-Up Studies; D005820:Genetic Testing / Q000379:methods; D006801:Humans; D008875:Middle Aged; D009006:Monosomy / Q000175:diagnosis*; D011247:Pregnancy; D011295:Prenatal Care / Q000379:methods; D011296:Prenatal Diagnosis / Q000379:methods*; D012189:Retrospective Studies; D055815:Young Adult