title: Prenatal diagnosis of trisomy 6 rescue resulting in paternal UPD6 with novel placental findings.
abstract: Uniparental disomy (UPD) is defined by the inheritance of both copies of a chromosome pair from one single parent. Although 23 cases of paternal UPD6 have been reported earlier, the occurrence of trisomy 6 rescue with paternal UPD6 has not been previously reported. The phenotype of paternal UPD6 results from biallelic expression of the maternally imprinted, paternally expressed ZAC and HYMAI genes, and includes transient neonatal diabetes mellitus (TNDM), intra-uterine growth restriction (IUGR), macroglossia, and minor anomalies. Trisomy rescue has been proposed as a pathogenic mechanism leading to UPD of other chromosomes. We report on the first case of a prenatally diagnosed infant with UPD6 and describe the clinical, cytogenetic, molecular, and novel placental findings in a female infant with paternal UPD6. Low-level trisomy 6 and paternal UPD6 were prenatally diagnosed through amniocentesis. After birth trisomy 6 was documented in the placenta but was not found in three different cell lines from the infant. The placenta was small with a peculiar pattern of vascular proliferation. Our results of trisomy 6 cells predominantly present in the placenta and only in low levels in the amniotic fluid suggest that the distribution and proportion of trisomic and diploid UPD cells contribute to the variability of fetal and placental phenotypes.
authors: Department of Pathology, University of Pittsburgh Medical Center, Pennsylvania, USA.
authors: Mariana M
authors: MM
authors: Cajaiba
authors: Selma
authors: S
authors: Witchel
authors: Suneeta
authors: S
authors: Madan-Khetarpal
authors: Jaqueline
authors: J
authors: Hoover
authors: Lori
authors: L
authors: Hoffner
authors: Trevor
authors: T
authors: Macpherson
authors: Urvashi
authors: U
authors: Surti
mesh_terms: D000015:Abnormalities, Multiple / Q000235:genetics; D000328:Adult; D000649:Amniocentesis; D002896:Chromosomes, Human, Pair 6; D019465:Craniofacial Abnormalities / Q000235:genetics; D005260:Female; D006801:Humans; D006943:Hyperglycemia / Q000188:drug therapy; D007223:Infant; D007231:Infant, Newborn; D007328:Insulin / Q000627:therapeutic use; D019656:Loss of Heterozygosity; D008661:Metabolism, Inborn Errors / Q000188:drug therapy; D010920:Placenta / Q000002:abnormalities*; D020641:Polymorphism, Single Nucleotide; D011247:Pregnancy; D012151:Resuscitation; D014314:Trisomy / Q000175:diagnosis*; D024182:Uniparental Disomy / Q000175:diagnosis*
chemical_list: D007328:Insulin