23 (2), 2020 l 79-86 DOI: 10.2478/bjmg-2020-0023 CASE REPORT FETAL CYSTIC HYGROMA ASSOCIATED WITH TERMINAL 2p25.1 DUPLICATION AND TERMINAL 3p25.3 DELETION: CYTOGENETIC, FLUORESCENT IN SITU HYBRIDIZATION AND MICROARRAY FAMILIAL CHARACTERIZATION OF TWO DIFFERENT CHROMOSOMAL STRUCTURAL REARRANGEMENTS Stipoljev F1,2,*, Barbalic M3, Logara M3, Vicic A1, Vulic M4, Zekic Tomas S5, Gjergja Juraski R2,6 *Corresponding Author: Feodora Stipoljev, Ph.D., Associate Professor, Cytogenetic Laboratory, De- partment of Obstetrics and Gynecology, Clinical Hospital “Sveti Duh,” Sveti Duh 64, 10000 Zagreb, Croatia. Tel.: +385-1371-2273. Fax: +385-1374-5534. E-mail: [email protected] ABSTRACT Three of these (CNTN4, SETD5 and VHL) were curated by Clingene Dosage Gene Map and were given a high We report a prenatally diagnosed case of partial tri- haplo-insufficiency score. Genes affected by the unbal- somy 2p and partial monosomy 3p, resulting from unbal- anced translocation could have contributed to some spe- anced translocation (2;3)(p25.1;p25.3) of paternal origin. cific phenotypic changes of the fetus in late pregnancy. The Parents were non consanguineous Caucasians, with famil- application of different cytogenetic methods was essential ial history of recurrent miscarriages on the father’s side. in our case, allowing the detection of different types of Detailed sonographic examination of the fetus showed a structural chromosomal aberrations and more thorough septated cystic hygroma measuring 6 mm at 13 weeks’ genetic counseling for future pregnancies. gestation. Karyotyping and fluorescent in situ hybridi- Keywords: Array comparative genomic hybridiza- zation (FISH) analysis of cultured amniotic fluid cells tion (aCGH); Chromosome 2; Chromosome 3; Molecular revealed an unbalanced translocation der(3)t(2;3)(p25.1; karyotyping. p25.3) and apparently balanced inv(3)(p13p25.3) in a fe- tus. Parental cytogenetic evaluation using karyotyping INTRODUCTION and FISH analysis showed the presence of both a bal- anced translocation and a paracentric inversion in father Pure partial trisomy for the terminal short arm of t(2;3) (p25.1;p25.3) inv(3)(p13p25.3). Microarray analysis chromosome 2 is an extremely rare chromosomal aber- showed a 11.6 Mb deletion at 3p26.3-p25.3 and duplica- ration, described in only a few reports. Observed pheno- tion of 10.5 Mb at the 2p25.3-p25 region. The duplicated typical features included prenatal and postnatal growth region at 2p25.1p25.3 contains 45 different genes, where retardation, facial dysmorphia, congenital heart disease, 12 are reported as OMIM morbid genes with different genital hypoplasia, long widely spaced fingers/toes, and phenotypical implications. The deleted region at 3p26.3- hypotonia [1-4]. Contrarily, terminal deletion of chromo- p25.3 contains 65 genes, out of which 27 are OMIM genes. some 3p is classified as a 3p25-pter deletion syndrome (MIM 613792), while the associated phenotype depends on exact size and location of the deletion. Characteristic 1 Cytogenetic Laboratory, Department of Obstetrics and Gynecology, features include low birth weight, trigonocephaly, micro- Clinical Hospital “Sveti Duh,” Zagreb, Croatia cephaly, hypertelorism, micrognathia, ptosis, ear anoma- 2 Faculty of Medicine, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia lies, hypotonia, mental and growth retardation, whereas 3 Genom Ltd, Zagreb, Croatia polydactyly, congenital heart defects, gastrointestinal and 4 Department of Gynecology and Obstetrics, Split University Hospital renal anomalies are considered as variable features [5,6]. Centre, School of Medicine, University of Split, Croatia To date, only one case of unbalanced translocation 5 Pathology Department, University Hospital Centre Split, Split, Croatia, resulting in partial trisomy 2p and partial monosomy 3p School of Medicine, University of Split, Croatia has been reported [7]. Herein, we present a prenatally diag- 6 Srebrnjak Children’s Hospital, Zagreb, Croatia nosed case of partial trisomy 2p and partial monosomy 3p, 79 TRISOMY 2p AND MONOSOMY 3p resulting from unbalanced translocation (2;3)(p25.1;p25.3) a 11.6 Mb deletion at 3p26.3-p25.3 [arr(hg19)3p26.3p25.3 of paternal origin. As father is the carrier of the reciprocal (100, 389-11,723, 086) × 1), and duplication in size of 10.5 translocation 2p;3p and paracentric inversion of short arm Mb at 2p25.3-p25.1 [arr(hg19)2p25.3p25.1(39,193-10,595, of chromosome 3, this case emphasizes the importance of 414) × 3] [Figure 1(C) and 1(D)]. After extensive genetic using different cytogenetic methods for the purposes of counseling, the parents decided to terminate the pregnancy final diagnosis settlement. at 21 weeks’ gestation. Autopsy and external measurements of the male fetus CASE REPORT revealed a weight of 380.53 g, crown-heel length of 25 cm, crown-rump length of 17.5 cm and head circumfer- A 25-year-old gravida 2, para 0 (G2P0) was referred ence of 17.9 cm. All the measurements were consistent for ultrasonic evaluation of increased nuchal translucency with 21/22 gestational weeks. The fetus had a normally (NT) thickness, detected during routine first-trimester ultra- formed head without overriding of the skull bones. Ears sound screening at another hospital. Her previous pregnan- were low-set and posteriorly rotated. Hypertelorism and cy ended in spontaneous abortion at 17 weeks’ gestation. increased nuchal thickness were noted. Limbs were within The parents were non consanguineous Caucasians, while normal limits and external genitalia were in accordance familial history revealed recurrent miscarriages in the hus- with male sex. Internal examination of thoracic cavity re- band’s family. Detailed sonographic examination showed vealed normally formed heart, thymus and neck structures. a septated cystic hygroma measuring 6 mm, and chorionic The left lung contained two lobes, while the right lung had villus sampling (CVS) was performed at 13 weeks’ gesta- incomplete horizontal fissure giving the appearance of tion. Cytogenetic analysis of short- and long-term cultured undeveloped middle lobe, the oblique fissure was present. villi showed a male fetal karyotype with derivative chro- Abdominal organs were of normal size and position giv- mosome 3. Subsequent amniocentesis was performed at ing the gestational age. The testicles were located in the 17 weeks’ gestation. A second-trimester examination was abdomen, cut surface showed hemorrhage. unremarkable, except of discrete nuchal thickness. Paren- tal cytogenetic evaluation using karyotyping and FISH DISCUSSION analysis showed apparently balanced translocation and paracentric inversion in father t(2;3) (p25.1; p25.3)inv(3) We have presented an extremely rare, prenatally di- (p13p25.3) [Figure 1(A)]. Dual-color FISH was performed agnosed case of partial trisomy 2p25.3-p25.1 and partial on paternal peripheral blood lymphocytes [Figure 1(B)] and monosomy 3p26.3-p25.3 of paternal origin. To date, only cultured amniotic fluid cells according to the manufactur- one study by Chen et al. [7] from 1996 reported a very er’s instructions, using whole-chromosome painting probes similar unbalanced translocation involving partial 2p tri- (wcp2, wcp3; Cytocell Ltd., Cambridge, Cambridgeshire, somy and partial 3p monosomy. Both parents were pheno- UK) probes specific for cen-tromeres of chromosome 2 and typically normal and the mother was a balanced reciprocal 3 (D2Z1, D3Z1 Kreatech probes; Leica Biosystems Inc., translocation carrier 46,XX, t(2;3)(p25.3;p25). Prenatal Buffalo Grove, IL, USA), locus specific 3p25 (PPARγ; sonographic findings included single umbilical artery, Kreatech), and subtelomeric probes 2p and 3p (D2S52147, shortening of the long bones and hypertelorism, while D3S4558 Kreatech probes; Leica Biosystems). Classical 10-month follow-up revealed craniofacial dysmorphy, hy- cytogenetic and FISH analysis of cultured amniotic fluid potonia, growth and mental retardation. In our case, the cells revealed an unbalanced karyotype 46,XY,der(3)t(2;3) fetal karyotype showed an unbalanced translocation with (p25.1;p25.3)inv(3) (p13p25.3) pat in the fetus, resulting in a partial trisomy 2p25.1-pter, partial monosomy 3p25.3- partial trisomy 2p and partial monosomy 3p. Genomic DNA pter, and balanced paracentric inversion of chromosome 3 was isolated from cultured amniocytes using DNeasy® with breakpoint sites in 3p13 and 3p25.3, both of paternal Blood & Tissue Kit (Qiagen Inc., Valencia, CA, USA) ac- origin. The fetus had hypertelorism, low-set posteriorly cording to the manufacturer’s protocol. Array comprehen- rotated ears and cystic hygroma. Father is a carrier of sive genomic hybridization (aCGH) was carried out using two different structural rearrangements with a common SurePrint G3 CGH+SNP 180 K microarray from Agilent breakpoint in 3p25.3. As the total number of breakpoint Technologies (Santa Clara, CA, USA). Microarray slide sites is three, it cannot be classified as a complex chromo- was scanned with G4900DA SureScan Microarray Scanner somal rearrangement. The investigation of patients with (Agilent Technologies), and data were analyzed by Cytog- apparently one type of balanced structural chromosomal enomics 3.0.6.6 software (Agilent Technologies). Microar- abnormality can give unexpected findings of another ap- ray analysis confirmed unbalanced structural rearrangement parently cryptic balanced rearrangement, which can be in the fetus, and delineated exact breakpoint sites showing overcame with use of FISH analysis. 80 BALKAN JOURNAL OF MEDICAL GENETICS