Partial Monosomy 12p and Ring Chromosome 12 Mosaicism in a Male with Developmental Delay and Mild Dysmorphism

Abstract

Dupl~caUon 9p syndrome 1s a cl~mcally well described syndrome characterized b, growth retardauoq developmental delay, skeletal malformatrons and cran~ofac~al anomal~es We report a farmly starung w t h a male ~nfant born by c-secuon at 39 weeks geslatlon to a 38 yo G6 P 4-0-14 The pregnancy was remarkable for an abnormal MSAFP placmg the pregnancy at a 1 17 nsk for Down Syndrome The parem refused amruocentesls after recelvlng genetlc counselmg At 35 weeks gestauon a fetal ultrasound demonstrated rmld polyhydrarmnos borderline hydrocephalus and a urulateral nght pyelecmls along wth a proxlmal hydroureter The pauent had an unremarkable dellvery at an outs~de mUMlon w t h Apgars of 9 and L O Birth welglit was 4790g (>95%) Ten hours post del~verv the patlent began to develop slgruf~canr lymphedema of the nght lower extrermty wluch IS what brought hun to our attention On presentallon the pallent appeared WIII b~temporal narrowng, short palpebral fissures, and small deep set eyes The n g h~ extreuuty showed s~grukicant edema lnvolvlng the foot eaendlng to the dstal purtlon of the h g h An x-ray of the extrermty shoaed no fracture A cat scan of the head demonstrated a s e cerebral volume loss with a sl~ghtlv prominent left ventncle when compared to the nght A small left subdural hygroma was also noted A cardac echocardogram and a renal ultrasound were both normal Cytogenet~c study on penpheral blood lymphocytes revealed add~honal matenal on 9p A FISH pant for chromosome 9 mdcated that the extra matenal was d u p b m o n of 9 The G-band~ng panem suggested dupllcauon of 9p13p22 Penpheral blood was obtained From both parents and an ~dentlcal kary0t)pe \%as found m the mother T l~e mother was noted to have sinular p l i e n o~p~c features to tl~e proban4 namely short palpebral fissures and small deep set e\es The mother reported havlng a leanung d s a b~l~n as a cluld completing onl\ a 9' grade educauon Furlher fanul) luston showed tlie lnotllcr to Iia\e tluee other chlldren aU wltll anollier partner ages I I 16 and 19 years of age All 3 half s~bllngs to the proband are reponed as slow These slbllngs are currently belng worked up q<ogenet~call\ Slnce first described in 1970 more than 100 cases ha\e been reported alth a dupllcatlon In\ol\lng \ aslous slze segments of the 9p cluo~iiosome Famlllal cases In\e been reported ~1111 much less frequenm The cluucal features and cvtogenellc findlngs as compared to prevlous reported cases arll be presented 'university o f Toronto, ON, Canada.In routine analysis of cultured CVS and amniotic fluid (AF) a few tetraploid cells are almost always observed. However, they are usually assumed to be due to culture artifact and are rarely documented in the laboratory report. In some C V S studies tetraploidy has retrospectively been reported as a "false positive" result. W e present two cases which document the difficulty in interpreting tetraploidy.Case I: A F was obtained at 40 weeks gestation from a fetus with multiple congenital anomalies. Interphase FISH analysis using probes for 13.18,21,X ...