Shin-Wen Chen

Molecular cytogenetic characterization of mosaicism for a small supernumerary marker chromosome derived from chromosome 8 or r(8)(::p11.22→q11.21::) in an 18-year-old female with short stature, obesity, attention deficit hyperactivity disorder, and intellectual disability

OBJECTIVE We present molecular cytogenetic characterization of mosaicism for a small supernumerary marker chromosome (sSMC) derived from chromosome 8. MATERIALS AND METHODS An 18-year-old female presented with short stature, obesity, developmental delay, speech delay, dyslexia, attention deficit hyperactivity disorder, and intellectual disability. Cytogenetic analysis of the peripheral blood revealed a karyotype of 47,XX,+mar[22]/46,XX[18]. Array comparative genomic hybridization and metaphase fluorescence in situ hybridization analyses were performed on the peripheral blood to determine the origin and mosaicism of the sSMC, and quantitative fluorescent polymerase chain reaction was used to exclude uniparental disomy. RESULTS Array comparative genomic hybridization analysis of the blood revealed a result of arr 8p11.22q11.21 (39,136,065-49,725,726)×2.80 (Log2 ratio=0.49), consistent with 70-80% mosaicism, encompassing 33 OMIM genes including GOLGA7, AGPAT6, NKX6-3, KAT6A, and FNTA. The sSMC(8) was r(8)(::p11.22→q11.21::). Metaphase fluorescence in situ hybridization analysis using the probes of RP11-754D24 (8p11.21) and RP11-769N21 (8q11.21) showed the sSMC(8) in 12/27 of cultured lymphocytes. Quantitative fluorescent polymerase chain reaction analysis excluded uniparental disomy 8. CONCLUSION Mosaic sSMC(8) derived from r(8)(::p11.22→q11.21::) can be associated with obesity, intellectual disability, and attention deficit hyperactivity disorder.

Molecular cytogenetic characterization of mosaicism for a small supernumerary marker chromosome derived from chromosome 8 or r(8)(::p12→q13.1::) associated with phenotypic abnormalities

OBJECTIVE We present molecular cytogenetic characterization of mosaicism for a small supernumerary marker chromosome (sSMC) derived from chromosome 8. MATERIALS AND METHODS A 35-year-old woman underwent amniocentesis at 16 weeks of gestation because of advanced maternal age. Amniocentesis revealed a karyotype of 47,XY,+mar[20]/46,XY[39]. However, array comparative genomic hybridization analysis on the subcultured amniocytes revealed no genomic imbalance. Prenatal ultrasound showed bilateral ventriculomegaly, intrauterine growth restriction, and an enlarged right atrium. At 36 weeks of gestation, a 2380-g baby was delivered with mild facial dysmorphism. The baby postnatally manifested right hydronephrosis, vesicoureteral reflux, hypospadias, hypotonia, strabismus, developmental delay and mild mental retardation. Array comparative genomic hybridization and metaphase fluorescence in situ hybridization analyses were performed on the peripheral blood to determine the origin and mosaicism of the sSMC, and quantitative fluorescent polymerase chain reaction was used to exclude uniparental disomy. RESULTS The blood had a karyotype of 47,XY,+mar[17]/46,XY[23]. Array comparative genomic hybridization revealed arr 8p12q13.1 (33,476,753-67,428,722)×2.40 (Log2 ratio=0.24) encompassing 98 Online Mendelian Inheritance in Man (OMIM) genes including CHD7, consistent with 30-40% mosaicism for r(8)(::p12→q13.1::). Metaphase fluorescence in situ hybridization identified the sSMC(8) in 21/33 of cultured lymphocytes. Quantitative fluorescent polymerase chain reaction excluded uniparental disomy 8. CONCLUSION Mosaic sSMC(8) derived from r(8)(::p12→q13.1::) can present phenotypic abnormalities. Chromosome 8q12 duplication syndrome should be included in differential diagnosis when an sSMC(8) contains 8q12.2 and CHD7.

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

OBJECTIVE We present prenatal diagnosis of low-level mosaicism for trisomy 13 at amniocentesis associated with a favorable outcome. CASE REPORT A 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). CONCLUSION Low-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

OBJECTIVE We present fetoplacental cytogenetic discrepancy in a pregnancy with prenatally detected mosaic tetrasomy 12p by amniocentesis. CASE REPORT A 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. CONCLUSION Pregnancy 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.

Prenatal diagnosis and molecular cytogenetic characterization of de novo partial monosomy 3p (3p26.3→pter) and partial trisomy 16q (16q23.1→qter)

OBJECTIVE To present the prenatal diagnosis and molecular cytogenetic characterization of a de novo unbalanced reciprocal translocation. CASE REPORT A 37-year-old woman, G3P1, underwent amniocentesis at 17 weeks of gestation because of her advanced maternal age. Her husband was 38 years old. Amniocentesis revealed a derivative chromosome 3 with the deletion of terminal 3p and the addendum of an unknown extra chromosomal segment on the distal 3p. The parental karyotypes were normal. Prenatal ultrasound findings were unremarkable. Array comparative genomic hybridization (aCGH) analysis using cultured amniocytes revealed a 2.38-Mb deletion in 3p26.3 [arr 3p26.3 (1-2,380,760)×1] encompassing 15 genes, which included 3 OMIM genes CHL1, CNTN6, and CNTN4, and a 13.17-Mb duplication in 16q23.1-q24.3 [arr 16q23.1q24.3 (76,999,082-90,170,596)×3] encompassing 207 genes, which included 81 OMIM genes. The pregnancy was subsequently terminated, and a malformed fetus was delivered with facial dysmorphism. Postnatal cord blood analysis revealed a karyotype of 46,XY,der(3)t(3;16)(p26.3;q23.1)dn. Polymorphic DNA marker analysis by quantitative fluorescent polymerase chain reaction (QF-PCR) on the DNAs extracted from the placenta and parental blood showed a paternal origin of the aberrant chromosome. CONCLUSION The aCGH and QF-PCR analyses helped in delineating the genomic imbalance and parental origin of prenatally detected de novo unbalanced reciprocal translocation.

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

OBJECTIVE We 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. CASE REPORT A 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. CONCLUSION Fetuses with TD2 may present increased NT, early onset hydrocephalus, enlarged cerebellum and cisterna magna, and hydrancephaly on prenatal ultrasound.

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

OBJECTIVE We present prenatal diagnosis of a familial 1q21.1-q21.2 microdeletion in a fetus with polydactyly of left foot on prenatal ultrasound. CASE REPORT A 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. CONCLUSION Fetuses with a 1q21.1-q21.2 microdeletion may present polydactyly on prenatal ultrasound, and aCGH is helpful for prenatal diagnosis under such a circumstance.

Molecular cytogenetic characterization and prenatal diagnosis of familial Xp22.33 microdeletion encompassing short stature homeobox gene in a male fetus with a favorable outcome

a Department of Obstetrics and Gynecology, MacKay Memorial Hospital, Taipei, Taiwan b Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan c Department of Biotechnology, Asia University, Taichung, Taiwan d School of Chinese Medicine, College of Chinese Medicine, China Medical University, Taichung, Taiwan e Institute of Clinical and Community Health Nursing, National Yang-Ming University, Taipei, Taiwan f Department of Obstetrics and Gynecology, School of Medicine, National Yang-Ming University, Taipei, Taiwan g Genephile Bioscience Laboratory, Kos Obstetrics and Gynecology, Taipei, Taiwan h Department of Pediatrics, MacKay Memorial Hospital, Taipei, Taiwan i Department of Medicine, MacKay Medical College, New Taipei City, Taiwan j Department of Early Childhood Care, National Taipei University of Nursing and Health Sciences, Taipei, Taiwan k Gene Biodesign Co. Ltd, Taipei, Taiwan l Department of Bioengineering, Tatung University, Taipei, Taiwan

Pfeiffer syndrome with FGFR2 C342R mutation presenting extreme proptosis, craniosynostosis, hearing loss, ventriculomegaly, broad great toes and thumbs, maxillary hypoplasia, and laryngomalacia

a Department of Obstetrics and Gynecology, MacKay Memorial Hospital, Taipei, Taiwan b Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan c Department of Biotechnology, Asia University, Taichung, Taiwan d School of Chinese Medicine, College of Chinese Medicine, China Medical University, Taichung, Taiwan e Institute of Clinical and Community Health Nursing, National Yang-Ming University, Taipei, Taiwan f Department of Obstetrics and Gynecology, School of Medicine, National Yang-Ming University, Taipei, Taiwan g Department of Pediatrics, MacKay Memorial Hospital, Taipei, Taiwan h Department of Medicine, MacKay Medical College, New Taipei City, Taiwan i Department of Early Childhood Care, National Taipei University of Nursing and Health Sciences, Taipei, Taiwan j Department of Radiology, Hsinchu MacKay Memorial Hospital, Hsinchu, Taiwan k MacKay Medicine, Nursing and Management College, Taipei, Taiwan l Department of Bioengineering, Tatung University, Taipei, Taiwan

Recurrent 2q13 microduplication encompassing MALL, NPHP1, RGPD6, and BUB1 associated with autism spectrum disorder, intellectual disability, and liver disorder

OBJECTIVE We present recurrent 2q13 microduplication in a family with autism spectrum disorder (ASD), intellectual disability, and liver disorder. CASE REPORT A 45-year-old woman and her 52-year-old husband were referred for genetic counseling because of mental and liver disorders in their two sons and their planning for prenatal diagnosis of familial disorders in the future pregnancy. She and her husband were normal and healthy, but their 21-year-old elder son had suffered from ASD, severe intellectual disability, poor motor function, liver cirrhosis, and esophageal varices, and their 19-year-old younger son had suffered from ASD, mild intellectual disability, poor balance and coordination, hepatosplenomegaly, fatty liver, and mild liver cirrhosis. The karyotypes of the parents and sons were normal. Array comparative genomic hybridization of the family revealed a 686.5-kb 2q13 microduplication encompassing MALL, NPHP1, RGPD6, and BUB1 in the elder brother, a 658.9-kb 2q13 microduplication encompassing MALL, NPHP1, RGPD6, and BUB1 in the younger brother, and an 83.83-kb 2q13 microduplication encompassing NPHP1 in the asymptomatic father. CONCLUSION Recurrent phenotypic abnormality in the family with normal karyotype should include a differential diagnosis of pathogenic copy-number variations.