Prenatal diagnosis of mosaic ring chromosome 22 associated with cardiovascular abnormalities and intrauterine growth restriction.
OBJECTIVE
To present the prenatal diagnosis and perinatal findings of mosaic ring chromosome 22.


METHODS
Amniocentesis was performed at 18 gestational weeks because of an advanced maternal age. Cytogenetic analysis of the cultured amniotic fluid cells revealed mosaicism for ring chromosome 22, 45,XX,-22[6]/46,XX,r(22)(p13q13.31)[15]. Abnormal fetal sonographic findings included small for gestational age, a ventricular septal defect, and truncus arteriosus. The pregnancy was terminated. Additional phenotypic findings included hypertelorism, epicanthal folds, and abnormal ears. Cytogenetic analysis of the cord blood lymphocytes revealed a complex mosaic karyotype, 45,XX,-22[7]/46,XX,r(22)(p13q13.31)[82]/46,XX,idic r(22)(p13q13.31;p13q13.31)[11]. Cytogenetic analysis of the hepatocytes also revealed mosaic r(22) with mosaicism for idic r(22) and monosomy 22. The deletion of distal 22q and the duplication of 22q11.2 on idic r(22), and the distal 22q deletion on r(22) were demonstrated by fluorescent in situ hybridization (FISH) analysis using 22q terminal probes at 22q13 and a DiGeorge syndrome critical region probe at 22q11.2. The breakpoint on distal 22q13 and the extent of the duplication of 22q on idic r(22) was determined by examining polymorphic markers specific for chromosome 22 using quantitative fluorescent polymerase chain reaction assays. The chromosomal aberration was of maternal origin.


CONCLUSIONS
Molecular and FISH studies allow a better delineation of some prenatally detected aneuploidy syndromes and help elucidate the genetic pathogenesis. Fetuses having mosaic r(22) with a low level mosaicism for r(22) duplication/deletion may present cardiovascular abnormalities and intrauterine growth restriction on prenatal ultrasound.
Chen
Chih-Ping
CP
Department of Obstetrics and Gynecology, Mackay Memorial Hospital, Taipei, Taiwan, Republic of China. cpc_mmh@yahoo.com
Chern
Schu-Rern
SR
Chang
Tung-Yao
TY
Lee
Chen-Chi
CC
Chen
Li-Feng
LF
Tzen
Chin-Yuan
CY
Wang
Wayseen
W
Lin
Chen-Ju
CJ
Yang
Brian P T
BP
Yang
Lawrence S T
LS
D000015:Abnormalities, Multiple / Q000175:diagnosis / Q000235:genetics*; D000025:Abortion, Eugenic; D000328:Adult; D000649:Amniocentesis; D002892:Chromosomes, Human, Pair 22; D005260:Female; D005317:Fetal Growth Retardation / Q000000981:diagnostic imaging / Q000235:genetics*; D006330:Heart Defects, Congenital / Q000175:diagnosis / Q000235:genetics*; D006345:Heart Septal Defects, Ventricular / Q000000981:diagnostic imaging / Q000235:genetics; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008423:Maternal Age; D009030:Mosaicism; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D018566:Pregnancy, High-Risk; D012303:Ring Chromosomes; D014339:Truncus Arteriosus, Persistent / Q000000981:diagnostic imaging / Q000235:genetics; D016216:Ultrasonography, Prenatal