Wayseen Wang

Molecular cytogenetic analysis of de novo dup(5)(q35.2q35.3) and review of the literature of pure partial trisomy 5q

An 11‐year‐old girl presented with the phenotype of microcephaly, moderate mental retardation, motor retardation, short stature, strabismus, brachydactyly, and facial dysmorphism. She had undergone surgery for inguinal hernias. Detailed examinations of the heart and other internal organs revealed normal findings. Her karyotype was 46,XX,dup(5)(q35.2q35.3) de novo. Molecular cytogenetic analysis showed a paternally derived 5q35.2 → q35.3 direct duplication and led to a correlation between the particular genotype and phenotype. This is the first description of a direct duplication of 5q35.2 → q35.3. Our case represents the smallest distal duplication of chromosome 5q that is not associated with congenital heart defects. Our case also represents the smallest distal duplication of chromosome 5q that is associated with short stature and microcephaly. Mutations or deletions of the NSD1 gene, mapped to 5q35.2 → q35.3, has been known to cause Sotos syndrome with cerebral gigantism, macrocephaly, advanced bone age and overgrowth. Our case provides evidence that the gene dosage effect of the NSD1 gene causes a reversed phenotype of microcephaly and short stature.

Mosaic Trisomy 7 at Amniocentesis: Prenatal Diagnosis and Molecular Genetic Analyses

OBJECTIVE To present prenatal diagnosis and molecular genetic analyses of mosaic trisomy 7. MATERIALS, METHODS AND RESULTS A 38-year-old primigravid woman underwent amniocentesis at 19 weeks of gestation because of her advanced maternal age. Amniocentesis revealed a karyotype of 47,XY,+7[26]/46, XY[16]. Repeated amniocentesis at 21 weeks of gestation revealed a karyotype of 47,XY,+7[20]/46,XY[17]. Simultaneous cordocentesis revealed a karyotype of 46,XY in 100/100 cultured lymphocytes. Polymorphic DNA marker analyses of uncultured amniocytes and cord blood revealed a diallelic pattern with seemingly equal biparental inheritance of chromosome 7. Repeated cordocentesis and chorionic villus sampling at 23 weeks of gestation revealed a karyotype of 47,XY,+7[2]/46,XY[66] in cord blood and a karyotype of 47,XY,+7 in 24/24 cultured chorionic villi cells. Level II ultrasonography was normal. At 40 weeks of gestation, a 2,708 g normal male baby was delivered. The peripheral blood had a karyotype of 46,XY in 100/100 lymphocytes. Molecular analyses of placenta, urine, buccal swab, and peripheral blood revealed a diallelic pattern and seemingly equal biparental inheritance of chromosome 7 in all tissues. At 3 months of age, he manifested hypopigmented skin and inguinal hernia, but showed normal growth and mental development. Fluorescence in situ hybridization analysis of inguinal hernia sac tissue revealed that 19/100 (19%) of nuclei had three chromosome 7 signals. CONCLUSION Mosaic trisomy 7 at amniocentesis may be derived from a cell culture artifact from an undetected low level of trisomy 7 mosaicism in uncultured amniocytes, and can be associated with favorable fetal outcome if the blood has a normal karyotype or a very low level of mosaicism and if uniparental disomy for chromosome 7 is excluded.

Rapid aneuploidy diagnosis by multiplex ligation-dependent probe amplification and array comparative genomic hybridization in pregnancy with major congenital malformations

OBJECTIVE To report five cases of major congenital malformations associated with common aneuploidies detected by rapid aneuploidy diagnosis. CASE REPORTS The fetus in the first case presented cebocephaly, semilobar holoprosencephaly, and tetralogy of Fallot on ultrasound at 25 gestational weeks. Cordocentesis using multiplex ligation-dependent probe amplification to detect aneuploidies of chromosomes X, Y, 13, 18, and 21 in uncultured cord blood revealed three copies of all targets on chromosome 13 consistent with the diagnosis of trisomy 13. The fetus in the second case presented bilateral choroid plexus cysts, congenital diaphragmatic hernia, and club foot on ultrasound at 18 gestational weeks. Amniocentesis using array-based comparative genomic hybridization (aCGH) in uncultured amniocytes revealed a gain in the DNA dosage of chromosome 18 consistent with the diagnosis of trisomy 18. The fetus in the third case presented aortic stenosis and nuchal edema on ultrasound at 22 gestational weeks. Amniocentesis using aCGH in uncultured amniocytes revealed a result of monosomy X and Turner syndrome. The fetus in the fourth case presented nuchal cystic hygroma and ventriculomegaly on ultrasound at 17 gestational weeks. Amniocentesis using aCGH in uncultured amniocytes revealed a gain in the DNA dosage of chromosome 21 consistent with the diagnosis of trisomy 21. The fetus in the fifth case presented holoprosencephaly, omphalocele, and hydronephrosis on ultrasound at 17 gestational weeks. Amniocentesis using aCGH in uncultured amniocytes revealed a gain in the DNA dosage of chromosome 13 consistent with the diagnosis of trisomy 13. CONCLUSIONS Prenatal diagnosis of major congenital malformations should alert one to the possibility of chromosomal abnormalities. Multiplex ligation-dependent probe amplification and aCGH have the advantage of rapid aneuploidy diagnosis of common aneuploidies in cases with major congenital malformations.

A paternally derived inverted duplication of distal 14q with a terminal 14q deletion

A girl presented with a phenotype including neonatal hypotonia, psychomotor retardation, mental retardation, short stature, and facial dysmorphism. She demonstrated common features of both 14q31‐qter duplication and terminal 14q deletion. She had undergone surgery for patent ductus arteriosus and pyloric stenosis in infancy. Her karyotype was 46,XX,der(14) dup(14)(q32.3 q31.3)del(14)(q32.3). Molecular cytogenetic analysis showed a paternally derived 14q31.3‐q32.3 duplication and a terminal 14q deletion and led to the correlations between a particular genotype and phenotype. This is the first description of a deletion and inverted duplication of 14q, and adds 14q to the growing list of the inverted duplication associated with a terminal deletion.

Prenatal diagnosis of mosaic trisomy 8: Clinical report and literature review

OBJECTIVE To present prenatal diagnosis of mosaic trisomy 8 and to review the literature. MATERIALS, METHODS, AND RESULTS A 34-year-old woman underwent amniocentesis at 16 weeks of gestation because of advanced maternal age. Amniocentesis revealed a karyotype of 47,XY,+8[6]/46,XY[31]. Repeated amniocentesis at 21 weeks of gestation revealed a karyotype of 47,XY,+8[4]/46,XY[77]. Interphase fluorescence in situ hybridization analysis of uncultured amniocytes showed 25% (5/20) mosaicism for trisomy 8. Array comparative genomic hybridization (aCGH) and quantitative fluorescent polymerase chain reaction (QF-PCR) analyses of uncultured amniocytes revealed no genomic imbalance in chromosome 8. The result of QF-PCR excluded uniparental disomy 8. At 23 weeks of gestation, the woman underwent amniocentesis and cordocentesis at other hospitals. Amniocentesis revealed a karyotype of 47,XY,+8[6]/46,XY[10]. Cordocentesis revealed a karyotype of 47,XY,+8[1]/46,XY[29]. Level II ultrasound findings were unremarkable. The parents decided to continue the pregnancy. A 1373-g male baby was prematurely delivered at 29 weeks of gestation. The peripheral blood had a karyotype of 47,XY,+8[1]/46,XY[29]. The infant had normal growth and mental development at 4 months of age. CONCLUSION Fetuses with mosaic trisomy 8 are compatible with viability and can have a favorable outcome. QF-PCR and array comparative genomic hybridization have the limitation of detection of low-level mosaicism. We suggest that in instances of repeated amniocentesis for confirmation of mosaic trisomy 8, follow-up investigations should include interphase fluorescence in situ hybridization studies on uncultured amniocytes, uniparental disomy tests, and detailed ultrasound examinations.

Prenatal diagnosis of mosaic trisomy 2: discrepancy between molecular cytogenetic analyses of uncultured amniocytes and karyotyping of cultured amniocytes in a pregnancy with severe fetal intrauterine growth restriction.

Department of Obstetrics and Gynecology, Mackay Memorial Hospital, Taipei, Taiwan Department of Medical Research, Mackay Memorial Hospital, Taipei, Taiwan 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 Department of Obstetrics and Gynecology, School of Medicine, National Yang-Ming University, Taipei, Taiwan Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan Department of Obstetrics and Gynecology, National Taiwan University Hospital, Taipei, Taiwan Department of Bioengineering, Tatung University, Taipei, Taiwan

A de novo 7.9 Mb deletion in 22q13.2→qter in a boy with autistic features, epilepsy, developmental delay, atopic dermatitis and abnormal immunological findings

We report a 5-year-old boy with mental retardation, autistic features, epilepsy, developmental delay, atopic dermatitis and abnormal immunological findings, carrying a 7.9 Mb de novo deletion of chromosome 22q13.2→qter. This region contains the SHANK3, NCAPH2 and CYP2D6 genes which are associated with T-cell immune response. The present case provides evidence that 22q13 deletion syndrome may be associated with immune system dysfunction in addition to neuropsychiatric disorders.

Chromosome 1p32-p31 deletion syndrome: Prenatal diagnosis by array comparative genomic hybridization using uncultured amniocytes and association with NFIA haploinsufficiency, ventriculomegaly, corpus callosum hypogenesis, abnormal external genitalia, and intrauterine growth restriction

OBJECTIVE To present prenatal diagnosis of chromosome 1p32-p31 deletion syndrome with NFIA haploinsufficiency, ventriculomegaly, corpus callosum hypogenesis, abnormal external genitalia, and intrauterine growth restriction and to review the literature. MATERIALS, METHODS, AND RESULTS A 26-year-old, primigravid woman was referred for amniocentesis at 30 weeks of gestation because of hydrocephalus and short limbs. Prenatal ultrasound showed macrocephaly, prominent forehead, ventriculomegaly, corpus callosum hypogenesis, micrognathia, and ambiguous external genitalia. Amniocentesis was performed, and array comparative genomic hybridization using uncultured amniocytes revealed a 22.2-Mb deletion of 1p32.3-p31.1 [arr cgh 1p32.3p31.1 (55,500,291 bp-77,711,982 bp)×1] encompassing the genes of NFIA, GPR177, and 89 additional genes. Cytogenetic analysis revealed a karyotype of 46,XX,del(1)(p31.1p32.3)dn. At 33 weeks of gestation, a dead fetus was delivered with a body weight of 1536g (<5(th) centile); relative macrocephaly; a broad face; prominent forehead; hypertelorism; anteverted nostrils; micrognathia; low-set ears; and abnormal female external genitalia with labial fusion, labial hypertrophy, absence of vaginal opening, and clitoral hypertrophy. Polymorphic DNA marker analysis determined a paternal origin of the deletion. CONCLUSION Prenatal diagnosis of ventriculomegaly with an abnormal corpus callosum should alert subtle chromosome aberrations and prompt molecular cytogenetic investigation if necessary. Fetuses with chromosome 1p32-p31 deletion syndrome and haploinsufficiency of the NFIA gene may present ventriculomegaly, corpus callosum hypogenesis, abnormal external genitalia, and intrauterine growth restriction in the third trimester.

Unbalanced reciprocal translocations at amniocentesis

OBJECTIVE To present perinatal findings, modes of ascertainments, and modes of segregation in unbalanced reciprocal translocations detected at amniocentesis. MATERIALS AND METHODS Between January 1987 and July 2010, 40 cases with unbalanced reciprocal translocations were diagnosed by amniocentesis at Mackay Memorial Hospital, Taipei, Taiwan. The 40 cases originated from 29 families; 21 families with one case, 7 families with two cases, and 1 family with five cases. RESULTS Of 40 cases, 33 (82.5%) presented fetal ultrasound abnormalities and 7 (17.5%) presented no ultrasound abnormalities. Of 40 cases, 36 (90%) had a segregation mode of adjacent-1 2:2 segregation, 3 (7.5%) had a segregation mode of 3:1 segregation with tertiary trisomy, and 1 (2.5%) had a segregation mode of 3:1 segregation with tertiary monosomy. Of 29 families, 7 (24.1%) had de novo translocations and 22 (75.9%) had inherited translocations. In seven de novo cases, the main modes of ascertainments included abnormal ultrasound findings (n = 5) and advanced maternal age (n = 2). In 22 inherited families, the main modes of first ascertainment included abnormal ultrasound findings (n = 8), a previous aneuploid child (n = 8), advanced maternal age (n = 4), parental carrier status (n = 1), and abnormal maternal serum screening results (n = 1). Among 22 inherited families, 9 (40.9%) had a known parental carrier status, but 13 (59.1%) were unaware of parental carrier status at amniocentesis. CONCLUSION Unbalanced reciprocal translocations detected at amniocentesis are frequently associated with abnormal ultrasound findings. Prenatal diagnosis of an unbalanced translocation may incidentally detect a balanced translocation in the family. Prenatal diagnosis of fetal structural abnormalities should alert structural chromosome rearrangements and prompt cytogenetic analysis of the fetus and parents if necessary.

Array-CGH detection of a de novo 2.8 Mb deletion in 2q24.2-->q24.3 in a girl with autistic features and developmental delay.

We report a 3 years and 4 months old girl with autistic features, developmental delay, mental retardation, language impairment and dysmorphic features, carrying a 2.8 Mb de novo deletion of chromosome 2q24.2-->q24.3 detected by array-CGH. This region contains two neuronal voltage-gated sodium channel genes SCN2A and SCN3A.