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Prenatal findings and molecular cytogenetic analyses of partial trisomy 12q (12q24.32-->qter) and partial monosomy 21q (21q22.2-->qter).
Prenat Diagn. 2006 Apr; 26(4):313-20.PD

Abstract

OBJECTIVES

To present the prenatal findings and molecular cytogenetic analyses of partial trisomy 12q and partial monosomy 21q, and a review of the literature.

METHODS

Amniocentesis was performed at 23 gestational weeks in a 33-year-old woman because of abnormal sonographic findings. Amniocentesis revealed a derivative chromosome 21, or der(21), with a deletion on the region of 21q22.2 and an addendum of a small chromosomal segment of unknown origin. The maternal karyotype was subsequently found to be 46,XX,t(12;21)(q24.32;q22.2). Level II ultrasound showed microcephaly, micrognathia, a ventricular septal defect, and rocker-bottom feet. The pregnancy was terminated. A malformed infant was delivered without the phenotype of holoprosencephaly (HPE). Fluorescence in situ hybridization (FISH) and polymorphic DNA markers were used to investigate the involved chromosomal segments.

RESULTS

FISH study showed the absence of the signal of 21q subtelomeric probe and the presence of the signal of 12q subtelomeric probe in the der(21). The fetal karyotype was 46,XY,der(21) t(12;21)(q24.32;q22.2)mat. Genetic marker analysis showed a deletion at 21q22.2 and a breakpoint between D21S156 (present) and D21S1245 (absent). The deleted segment was measured about 4.5 Mb encompassing the HPE critical region.

CONCLUSIONS

Molecular genetic analyses help in determining the prenatally detected unbalanced cryptic translocation as well as parental balanced subtle translocation. A duplication of 12q24.32-->qter and a deletion of 21q22.2-->qter may be associated with prenatal sonographic findings of microcephaly, borderline ventriculomegaly and cerebellar hypoplasia, micrognathia, a ventricular septal defect, and rocker-bottom feet. Haploinsufficiency of the HPE critical region at 21q22.3 may not cause an HPE phenotype.

Authors+Show Affiliations

Department of Obstetrics and Gynecology, Mackay Memorial Hospital, Taipei, Taiwan. cpc_mmh@yahoo.comNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Case Reports
Journal Article
Research Support, Non-U.S. Gov't
Review

Language

eng

PubMed ID

16506269

Citation

Chen, Chih-Ping, et al. "Prenatal Findings and Molecular Cytogenetic Analyses of Partial Trisomy 12q (12q24.32-->qter) and Partial Monosomy 21q (21q22.2-->qter)." Prenatal Diagnosis, vol. 26, no. 4, 2006, pp. 313-20.
Chen CP, Chern SR, Lin CC, et al. Prenatal findings and molecular cytogenetic analyses of partial trisomy 12q (12q24.32-->qter) and partial monosomy 21q (21q22.2-->qter). Prenat Diagn. 2006;26(4):313-20.
Chen, C. P., Chern, S. R., Lin, C. C., Wang, T. H., Li, Y. C., Hsieh, L. J., Lee, C. C., Hua, H. M., & Wang, W. (2006). Prenatal findings and molecular cytogenetic analyses of partial trisomy 12q (12q24.32-->qter) and partial monosomy 21q (21q22.2-->qter). Prenatal Diagnosis, 26(4), 313-20.
Chen CP, et al. Prenatal Findings and Molecular Cytogenetic Analyses of Partial Trisomy 12q (12q24.32-->qter) and Partial Monosomy 21q (21q22.2-->qter). Prenat Diagn. 2006;26(4):313-20. PubMed PMID: 16506269.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Prenatal findings and molecular cytogenetic analyses of partial trisomy 12q (12q24.32-->qter) and partial monosomy 21q (21q22.2-->qter). AU - Chen,Chih-Ping, AU - Chern,Schu-Rern, AU - Lin,Chyi-Chyang, AU - Wang,Tzu-Hao, AU - Li,Yueh-Chun, AU - Hsieh,Lie-Jiau, AU - Lee,Chen-Chi, AU - Hua,Hui-Min, AU - Wang,Wayseen, PY - 2006/3/1/pubmed PY - 2006/8/19/medline PY - 2006/3/1/entrez SP - 313 EP - 20 JF - Prenatal diagnosis JO - Prenat Diagn VL - 26 IS - 4 N2 - OBJECTIVES: To present the prenatal findings and molecular cytogenetic analyses of partial trisomy 12q and partial monosomy 21q, and a review of the literature. METHODS: Amniocentesis was performed at 23 gestational weeks in a 33-year-old woman because of abnormal sonographic findings. Amniocentesis revealed a derivative chromosome 21, or der(21), with a deletion on the region of 21q22.2 and an addendum of a small chromosomal segment of unknown origin. The maternal karyotype was subsequently found to be 46,XX,t(12;21)(q24.32;q22.2). Level II ultrasound showed microcephaly, micrognathia, a ventricular septal defect, and rocker-bottom feet. The pregnancy was terminated. A malformed infant was delivered without the phenotype of holoprosencephaly (HPE). Fluorescence in situ hybridization (FISH) and polymorphic DNA markers were used to investigate the involved chromosomal segments. RESULTS: FISH study showed the absence of the signal of 21q subtelomeric probe and the presence of the signal of 12q subtelomeric probe in the der(21). The fetal karyotype was 46,XY,der(21) t(12;21)(q24.32;q22.2)mat. Genetic marker analysis showed a deletion at 21q22.2 and a breakpoint between D21S156 (present) and D21S1245 (absent). The deleted segment was measured about 4.5 Mb encompassing the HPE critical region. CONCLUSIONS: Molecular genetic analyses help in determining the prenatally detected unbalanced cryptic translocation as well as parental balanced subtle translocation. A duplication of 12q24.32-->qter and a deletion of 21q22.2-->qter may be associated with prenatal sonographic findings of microcephaly, borderline ventriculomegaly and cerebellar hypoplasia, micrognathia, a ventricular septal defect, and rocker-bottom feet. Haploinsufficiency of the HPE critical region at 21q22.3 may not cause an HPE phenotype. SN - 0197-3851 UR - https://www.unboundmedicine.com/medline/citation/16506269/Prenatal_findings_and_molecular_cytogenetic_analyses_of_partial_trisomy_12q__12q24_32__>qter__and_partial_monosomy_21q__21q22_2__>qter__ L2 - https://doi.org/10.1002/pd.1399 DB - PRIME DP - Unbound Medicine ER -