Prenatal diagnosis of the Dandy-Walker malformation and ventriculomegaly associated with partial trisomy 9p and distal 12p deletion.
OBJECTIVE
To present the prenatal diagnosis and perinatal findings of partial trisomy 9p and distal 12p deletion.


RESULTS
Amniocentesis was performed at 17 gestational weeks due to a balanced reciprocal translocation t(9;12)(p11.2;p13.3) in the mother. The father's karyotype was normal. The family had a 5-year-old daughter with a Dandy-Walker malformation and a trisomy 9p syndrome. Cytogenetic analysis of the cultured amniotic fluid cells revealed a 46,XY,der(12)t(9;12)(p11.2;p13.3)mat karyotype with partial monosomy 12p(12pter-->p13.3) and partial trisomy 9p(9pter-->p11.2). Sonographic examination of the fetal brain and skull showed bilateral ventriculomegaly, brachycephaly and a Dandy-Walker malformation with an enlarged cisterna magna and absence of the cerebellar vermis. The pregnancy was terminated subsequently. At autopsy, the proband manifested agenesis of the cerebellar vermis and a typical trisomy 9p phenotype.


CONCLUSIONS
Fetuses with partial trisomy 9p(9pter-->p11.2) may present a Dandy-Walker malformation and ventriculomegaly on prenatal ultrasound in the second trimester. A dosage effect of genes located on 9pter-->p11.2 may be associated with the abnormal development of the central nervous system in patients with partial or complete trisomy 9.
Chen
Chih-Ping
CP
Department of Obstetrics and Gynecology, Mackay Memorial Hospital, Taipei, Taiwan, Republic of China. cpc_mmh@yahoo.com
Chang
Tung-Yao
TY
Shih
Jin-Chung
JC
Lin
Shuan-Pei
SP
Lin
Chen-Ju
CJ
Wang
Wayseen
W
Lee
Chen-Chi
CC
Town
Dai-Dyi
DD
Pan
Chen-Wen
CW
Tzen
Chin-Yuan
CY
D000328:Adult; D000649:Amniocentesis; D001921:Brain / Q000002:abnormalities; D002478:Cells, Cultured; D002871:Chromosome Banding; D002872:Chromosome Deletion; D002881:Chromosomes, Human, Pair 12; D002899:Chromosomes, Human, Pair 9; D003616:Dandy-Walker Syndrome / Q000000981:diagnostic imaging / Q000235:genetics* / Q000473:pathology; D005260:Female; D005865:Gestational Age; D006352:Heart Ventricles / Q000002:abnormalities* / Q000000981:diagnostic imaging; D006801:Humans; D011247:Pregnancy; D014314:Trisomy / Q000235:genetics* / Q000473:pathology; D016216:Ultrasonography, Prenatal