Prenatal diagnosis and molecular cytogenetic characterization of de novo partial trisomy 7p (7p15.3→pter) and partial monosomy 13q (13q33.3→qter) associated with Dandy-Walker malformation, abnormal skull development and microcephaly.
OBJECTIVE
To present the prenatal diagnosis and molecular cytogenetic characterization of de novo partial trisomy 7p (7p15.3→pter) and partial monosomy 13q (13q33.3→qter) associated with Dandy-Walker malformation (DWM), abnormal skull development, microcephaly and multiple congenital anomalies.


RESULTS
A 42-year-old woman, gravida 6, para 1, was referred for amniocentesis at 18 weeks of gestation because of her advanced maternal age. Amniocentesis revealed an aberrant derivative chromosome 13, or der(13). The parental karyotypes were normal. Spectral karyotyping showed that the der(13) was derived from a translocation of chromosomes 7 and 13. Fluorescence in situ hybridization using subtelomeric probes revealed three signals of 7pTEL and only one signal of 13qTEL, indicating a translocation between 7p and 13q in the der(13). Array-based comparative genomic hybridization demonstrated partial trisomy 7p (7p15.3-p22.3) and partial monosomy 13q (13q33.3-q34). The karyotype was 46,XY,der(13)t(7;13)(p15.3;q33.3). Polymorphic DNA marker analysis revealed the paternal origin of the aberrant chromosome. Level II ultrasound at 24 weeks of gestation revealed microcephaly, an irregular-shaped skull, DWM, nuchal edema and transposition of the great arteries.


CONCLUSIONS
Spectral karyotyping, fluorescence in situ hybridization and array-based comparative genomic hybridization are useful for prenatal investigation of the nature of a de novo aberrant derivative chromosome. Partial trisomy 7p (7p15.3→pter) and partial monosomy 13q (13q33.3→qter) can be associated with DWM, microcephaly, abnormal skull development, nuchal edema and cardiovascular defects on prenatal ultrasound.
Department of Obstetrics and Gynecology, Mackay Memorial Hospital, Taipei, Taiwan. cpc_mmh@yahoo.com
Chih-Ping
CP
Chen
Ming
M
Chen
Yi-Ning
YN
Su
Fuu-Jen
FJ
Tsai
Schu-Rern
SR
Chern
Chin-Yuan
CY
Hsu
Pei-Chen
PC
Wu
Dai-Dyi
DD
Town
Dong-Jay
DJ
Lee
Gwo-Chin
GC
Ma
Wayseen
W
Wang
D000015:Abnormalities, Multiple / Q000175:diagnosis / Q000235:genetics; D000328:Adult; D002869:Chromosome Aberrations; D002872:Chromosome Deletion; D025063:Chromosome Disorders / Q000175:diagnosis / Q000235:genetics; D002882:Chromosomes, Human, Pair 13 / Q000235:genetics; D002897:Chromosomes, Human, Pair 7 / Q000235:genetics; D003616:Dandy-Walker Syndrome / Q000175:diagnosis / Q000235:genetics*; D005260:Female; D006801:Humans; D008297:Male; D008831:Microcephaly / Q000175:diagnosis / Q000235:genetics*; D011247:Pregnancy; D011296:Prenatal Diagnosis; D012886:Skull / Q000002:abnormalities*; D014178:Translocation, Genetic; D014314:Trisomy / Q000175:diagnosis / Q000235:genetics