Tzu-Yun Chuang

Prenatal diagnosis of low-level mosaicism for trisomy 13 at amniocentesis associated with a favorable outcome

OBJECTIVEnWe present prenatal diagnosis of low-level mosaicism for trisomy 13 at amniocentesis associated with a favorable outcome.nnnCASE REPORTnA 35-year-old woman underwent amniocentesis at 18 weeks of gestation because of advanced maternal age. Amniocentesis revealed a karyotype of 47,XY,+13[5]/46,XY[20]. Oligonucleotide array comparative genomic hybridization (aCGH) analysis on uncultured amniocytes revealed arr [GRCh37] (13)×3 [0.10], (X,Y)×1 compatible with trisomy 13 mosaicism. Prenatal ultrasound was unremarkable. Repeat amniocentesis was performed at 21 weeks of gestation. Interphase fluorescence in situ hybridization (FISH) analysis on uncultured amniocytes revealed a mosaic trisomy 13 level of 10% (10/100 cells). aCGH analysis on uncultured amniocytes revealed a result of arr 13q12.11q34 (20,407,323-115,092,619)×2.1 with a log2 ratio of 0.06 compatible with a 10% level of mosaicism. Polymorphic DNA marker analysis excluded uniparental disomy 13. The parental karyotypes were normal. Conventional cytogenetic analysis using cultured amniocytes at repeat amniocentesis revealed a karyotype of 46,XY in 23/23 colonies. The pregnancy was carried to 37 weeks of gestation, and a 3600-g phenotypically normal male baby was delivered. When examined at 8 months of age, the infant was doing well and was normal in psychomotor and growth development. The peripheral blood had a karyotype of 46,XY, and interphase FISH analysis on uncultured urinary cells revealed a mosaic trisomy 13 level of 4.4% (2/45 cells).nnnCONCLUSIONnLow-level true mosaicism for trisomy 13 at amniocentesis without ultrasound abnormalities can be associated with a favorable fetal outcome.

Fetoplacental cytogenetic discrepancy in a pregnancy with fetal mosaic tetrasomy 12p and Pallister–Killian syndrome detected by amniocentesis

OBJECTIVEnWe present fetoplacental cytogenetic discrepancy in a pregnancy with prenatally detected mosaic tetrasomy 12p by amniocentesis.nnnCASE REPORTnA 34-year-old woman underwent amniocentesis at 17 weeks of gestation because of advanced maternal age. Cytogenetic analysis of cultured amniocytes revealed a karyotype of 47,XX,+i(12)(p10)[7]/46,XX[16]. Array comparative genomic hybridization (aCGH) analysis of the DNA extracted from cultured amniocytes revealed arr (12p)×3, (X)×2. Prenatal ultrasound findings were unremarkable. The pregnancy was subsequently terminated, and a fetus was delivered with facial dysmorphism consistent with the clinical features of Pallister-Killian syndrome (PKS). Postnatal cytogenetic analysis of the cultured cells from umbilical cord, skin, cord blood and placenta revealed 47,XX,+i(12)(p10)[6]/46,XX[34] in umbilical cord, 47,XX,+i(12)(p10)[11]/46,XX[29] in skin, 47,XX,+i(12)(p10)[3]/46,XX[47] in cord blood and 46,XX[40] in placenta. The mosaic tetrasomy 12p levels of the umbilical cord, skin, cord blood and placenta were 15%, 27.5%, 6% and 0%, respectively. aCGH analysis of the DNA extracted from uncultured cord blood and placenta revealed arr 12p13.33p11.1 (230,421-34,756,209)×3.0 in cord blood but no genomic imbalance in placenta. Polymorphic DNA marker analysis showed a maternal origin of the supernumerary isochromosome 12p in cord blood but biparental inheritance with equal fluorescent activity in placenta.nnnCONCLUSIONnPregnancy with fetal PKS and mosaic tetrasomy 12p may present fetoplacental cytogenetic discrepancy. Therefore, genetic analysis on placenta alone may fail to detect fetal mosaic tetrasomy 12p associated with PKS.

A 13-year-old girl with 18p deletion syndrome presenting Turner syndrome-like clinical features of short stature, short webbed neck, low posterior hair line, puffy eyelids and increased carrying angle of the elbows

OBJECTIVEnWe report a 13-year-old girl with 18p deletion syndrome presenting Turner syndrome-like clinical features.nnnCASE REPORTnA 13-year-old girl was referred for genetic counseling of Turner syndrome-like clinical features of short stature, short webbed neck, low posterior hair line, puffy eyelids and increased carrying angle of the elbows. The girl also had mild intellectual disability, psychomotor developmental delay, speech disorder, high-arched palate, hypertelorism and mid-face hypoplasia. Cytogenetic analysis of the girl revealed a karyotype of 46,XX,del(18) (p11.2). The parental karyotypes were normal. Array comparative genomic hybridization analysis on the DNA extracted from the peripheral blood revealed a 13.93-Mb deletion of 18p11.32-p11.21 or arr 18p11.32p11.21 (148,993-14,081,858)xa0×xa01.0 [GRCh37 (hg19)] encompassing 52 Online Mendelian Inheritance in Man (OMIM) genes including USP14, TYMS, SMCHD1, TGIF1, LAMA1, TWSG1, GNAL and PTPN2. Polymorphic DNA marker analysis revealed a maternal origin of the deletion.nnnCONCLUSIONnFemales with Turner syndrome-like clinical features in association with intellectual disability, facial dysmorphism and psychomotor developmental delay should be suspected of having chromosome deletion syndromes.

Prenatal diagnosis of short-rib polydactyly syndrome type III or short-rib thoracic dysplasia 3 with or without polydactyly (SRTD3) associated with compound heterozygous mutations in DYNC2H1 in a fetus

OBJECTIVEnWe present the perinatal imaging findings and molecular genetic analysis in a fetus with short-rib polydactyly syndrome (SRPS) type III or short-rib thoracic dysplasia 3 with or without polydactyly (SRTD3).nnnCASE REPORTnA 29-year-old, primigravid woman was referred for genetic counseling at 15 weeks of gestation because of abnormal ultrasound findings of short limbs, a narrow chest and bilateral polydactyly of the hands and feet, consistent with a diagnosis of SRPS type III. Chorionic villus sampling was performed, and targeted next-generation sequencing (NGS) was applied to analyze a panel of 25 genes including CEP120, DYNC2H1, DYNC2LI1, EVC, EVC2, FGFR2, FGFR3, HOXD10, IFT122, IFT140, IFT172, IFT52, IFT80, KIAA0586, NEK1, PAPSS2, SLC26A2, SOX9, TCTEX1D2, TCTN3, TTC21B, WDR19, WDR34, WDR35 and WDR60. The NGS analysis identified novel mutations in the DYNC2H1 gene. The fetus was compound heterozygous for a missense mutation c.8077Gxa0>xa0T (p.Asp2693Tyr) of paternal origin in DYNC2H1 and a frameshift mutation c.11741_11742delTT (p.Phe3914X) of maternal origin in DYNC2H1. The fetus had a karyotype of 46,XY, and postnatally manifested characteristic SRPS type III phenotype.nnnCONCLUSIONnTargeted NGS is useful in genetic diagnosis of fetal skeletal dysplasia and SRPS, and the information acquired is helpful in genetic counseling.

Prenatal diagnosis of hydrancephaly and enlarged cerebellum and cisterna magna in a fetus with thanatophoric dysplasia type II and a review of prenatal diagnosis of brain anomalies associated with thanatophoric dysplasia

OBJECTIVEnWe present prenatal diagnosis of hydrancephaly and enlarged cerebellum and cisterna magna in a fetus with thanatophoric dysplasia type II (TD2) and a review of prenatal diagnosis of brain anomalies associated with TD.nnnCASE REPORTnA 33-year-old woman was referred for genetic counseling at 25 weeks of gestation because of fetal ultrasound abnormalities. Prenatal ultrasound at 14 weeks of gestation revealed an increased nuchal translucency (NT) and hydrocephalus. Level II ultrasound examination at 25 weeks of gestation revealed hydrancephaly, macrocephaly, a cloverleaf skull, frontal bossing, enlarged cerebellum and cisterna magna, a narrow chest, small ribs, short straight limbs. Amniocentesis revealed a karyotype of 46,XX. FGFR3 mutation analysis using the DNA extracted from uncultured amniocytes revealed a genotype of WT/c.1948A>G (p.Lys650Glu). The result was consistent with a K650E mutation in FGFR3 and TD2. The pregnancy was subsequently terminated.nnnCONCLUSIONnFetuses with TD2 may present increased NT, early onset hydrocephalus, enlarged cerebellum and cisterna magna, and hydrancephaly on prenatal ultrasound.

Prenatal diagnosis of a familial 5p14.3-p14.1 deletion encompassing CDH18, CDH12, PMCHL1, PRDM9 and CDH10 in a fetus with congenital heart disease on prenatal ultrasound

OBJECTIVEnWe present prenatal diagnosis of a familial 5p14.3-p14.1 deletion in a fetus with congenital heart disease on prenatal ultrasound.nnnCASE REPORTnA 33-year-old woman underwent amniocentesis at 18 weeks of gestation because of fetal ventricular septal defect (VSD) and echogenic bowel on prenatal ultrasound. Amniocentesis revealed a karyotype of 46,XX,del (5) (p14p14). Simultaneous array comparative genomic hybridization (aCGH) analysis on the DNA extracted from uncultured amniocytes revealed a 5.589-Mb 5p14.3-p14.1 deletion or arr 5p14.3p14.1 (19, 497, 649-25,086,268)xa0×xa01.0 [GRCh37 (hg19)] encompassing CDH18, CDH12, PMCHL1, PRDM9 and CDH10. Cytogenetic and aCGH analyses of the parents showed that the phenotypically normal mother carried the 5p14.3-p14.1 deletion. The father did not have such a deletion. The parents elected to continue the pregnancy, and a 3426-g female baby was delivered at 38 weeks of gestation with no gross abnormalities. The infant postnatally manifested VSD, atrial septal defect and patent ductus areriosus, and underwent cardiac surgery to treat the congenital heart disease. When follow-up at age 1 year and 4 months, she had a body weight of 8.8xa0Kg (50th-75th centile), a body height of 75.6xa0cm (85th-95th centile) and normal psychomotor development.nnnCONCLUSIONnFetuses with a 5p14.3-p14.1 deletion may present congenital heart disease on prenatal ultrasound, and aCGH is helpful for prenatal diagnosis under such a circumstance.

Prenatal diagnosis of a familial 1q21.1-q21.2 microdeletion in a fetus with polydactyly of left foot on prenatal ultrasound

OBJECTIVEnWe present prenatal diagnosis of a familial 1q21.1-q21.2 microdeletion in a fetus with polydactyly of left foot on prenatal ultrasound.nnnCASE REPORTnA 30-year-old, gravida 2, para 1, woman underwent amniocentesis at 22 weeks of gestation because of fetal polydactyly of left foot and echogenic heart foci on prenatal ultrasound. She and her husband and the 2-year-old son were healthy, and there was no family history of mental disorders, skeletal abnormalities and congenital malformations. Amniocentesis revealed a karyotype of 46,XX. Simultaneous array comparative genomic hybridization (aCGH) analysis on the DNA extracted from uncultured amniocytes revealed a 1.317-Mb 1q21.1-q21.2 microdeletion encompassing PRKAB2, FMO5, CHD1L, BCL9, ACP6, GJA5, GJA8 and GPR89B. aCGH analysis of the family members revealed that the phenotypically normal father and elder son carried the same 1q21.1-q21.2 microdeletion. The mother did not have such a deletion. The parents elected to continue the pregnancy, and a 3416-g female baby was delivered at 40 weeks of gestation with neither facial dysmorphism nor gross abnormalities except postaxial polydactyly of the left foot.nnnCONCLUSIONnFetuses with a 1q21.1-q21.2 microdeletion may present polydactyly on prenatal ultrasound, and aCGH is helpful for prenatal diagnosis under such a circumstance.

Prenatal diagnosis of a 3.2-Mb 2p16.1-p15 duplication associated with familial intellectual disability

OBJECTIVEnWe present prenatal diagnosis of a 2p16.1-p15 duplication associated with familial intellectual disability, and we discuss the genotype-phenotype correlation.nnnCASE REPORTnA 22-year-old, primigravid woman underwent amniocentesis at 22 weeks of gestation because of a family history of intellectual disability. The woman and her two sisters had intellectual disability but no behavioral disorders. The intellectual disability was noted in at least one paternal aunt and six paternal cousins of the woman. Cytogenetic analysis revealed the karyotype of 46,XX in the fetus and the two women. Array comparative genomic hybridization (aCGH) analysis on the DNAs extracted from cultured amniocytes and the bloods of the woman and the her sister revealed a 3.244-Mb duplication of 2p16.1-p15 or arr 2p16.1p15 (58,288,588-61,532,538)xa0×xa03.0 [GRCh37 (hg19)] encompassing eight Online Mendelian Inheritance in Man (OMIM) genes of VRK2, FANCL, BCL11A, PAPOLG, REL, PUS10, PEX13 and USP34 in the fetus and the two women. Prenatal ultrasound findings were unremarkable. The woman elected to continue the pregnancy. A 3244-g female baby was delivered at term with neither craniofacial dysmorphism nor structural abnormalities.nnnCONCLUSIONnaCGH is useful in prenatal diagnosis of inherited subtle chromosome imbalance in pregnancy with familial intellectual disability. Chromosome 2p16.1-p15 duplication can be associated with intellectual disability.

Prenatal diagnosis of a familial 15q11.2 (BP1-BP2) microdeletion encompassing TUBGCP5, CYFIP1, NIPA2 and NIPA1 in a fetus with ventriculomegaly, microcephaly and intrauterine growth restriction on prenatal ultrasound

OBJECTIVEnWe present prenatal diagnosis of a 15q11.2 (BP1-BP2) microdeletion encompassing TUBGCP5, CYFIP1, NIPA2 and NIPA1 in a fetus with ventriculomegaly, microcephaly and intrauterine growth restriction (IUGR) on prenatal ultrasound.nnnCASE REPORTnA 30-year-old, gravida 3, para 2, woman was referred to the hospital for amniocentesis because of fetal ventriculomegaly on prenatal ultrasound. Her husband was 31 years old. The couple had two healthy daughters, and there was no family history of mental disorders and congenital malformations. Amniocentesis revealed a karyotype of 46,XX. Array comparative genomic hybridization (aCGH) analysis on the DNA extracted from uncultured amniocytes revealed a 451.89-kb 15q11.2 microdeletion or arr 15q11.2 (22,765,628-23,217,514)xa0×xa01.0 [GRCh37 (hg19)] encompassing TUBGCP5, CYFIP1, NIPA2 and NIPA1. The parental karyotypes were normal. aCGH analysis on the DNAs extracted from parental bloods revealed a 402-kb 15q11.2 microdeletion or arr 15q11.2 (22,815,577-23,217,514)xa0×xa01.0 (hg19) encompassing TUBGCP5, CYFIP1, NIPA2 and NIPA1 in the phenotypically normal father. The mother did not have any genomic imbalance. Level II ultrasound at 21 weeks of gestation revealed microcephaly and IUGR. The parents elected to terminate the pregnancy at 22 weeks of gestation, and a female fetus was delivered with a body weight of 448xa0g (10th centile) and a body length of 26xa0cm (3rd-10th centile) but no gross abnormalities.nnnCONCLUSIONnFetuses with a 15q11.2 (BP1-BP2) microdeletion may present ventriculomegaly, microcephaly and IUGR on prenatal ultrasound, and aCGH is helpful for prenatal diagnosis under such a circumstance.

Prenatal diagnosis of a 0.7-Mb 17p13.3 microdeletion encompassing YWHAE and CRK but not PAFAH1B1 in a fetus without ultrasound abnormalities

OBJECTIVEnWe present prenatal diagnosis and molecular cytogenetic characterization of 17p13.3 microdeletion encompassing YWHAE and CRK but not PAFAH1B1 in a fetus without ultrasound abnormalities.nnnCASE REPORTnA 33-year-old woman underwent amniocentesis at 17 weeks of gestation because of a family history of spinocerebellar atrophy in the husband. Amniocentesis revealed a karyotype of 46,XX. Simultaneously array comparative genomic hybridization (aCGH) analysis (using 60,000 probes) revealed a 0.7-Mb 17p13.3 microdeletion or arr 17p13.3 (1,264,243-1,965,733)xa0×xa01 dn [GRCh37 (hg19)] encompassing YWHAE and CRK but not PAFAH1B1. Prenatal ultrasound findings were unremarkable. There were no structural abnormalities of the brain, heart, kidneys, skull, limbs and other internal organs. The parents elected to terminate the pregnancy, and a 268-g fetus was delivered at 19 weeks of gestation with mild facial dysmorphism. Postnatal high-resolution aCGH analysis of the placenta (using 630,000 probes) showed a 0.79-Mb 17p13.3 microdeletion or arr 17p13.3 (1,173,549-1,970,690)xa0×xa01 (hg19) encompassing TUSC5, YWHAE, CRK and HIC1 but not PAFAH1B1. Metaphase fluorescence in situ hybridization analysis using the 17p13.3-specific probe of RP11-818O24 revealed a 17p13.3 deletion.nnnCONCLUSIONnFetus with 17p13.3 microdeletion without involving PAFAH1B1 may present no brain abnormalities on fetal ultra sound.