Prenatal diagnosis of 4p and 4q subtelomeric microdeletion in de novo ring chromosome 4.
Ring chromosomes are unusual abnormalities that are observed in prenatal diagnosis. A 23-year-old patient (gravida 1, para 0) referred for amniocentesis due to abnormal maternal serum screening result in the 16th week of second pregnancy. Cytogenetic analysis of cultured amniyotic fluid cells revealed out ring chromosome 4. Both maternal and paternal karyotypes were normal. Terminal deletion was observed in both 4p and 4q arms of ring chromosome 4 by fluorescence in situ hybridization (FISH). However deletion was not observed in the WHS critical region of both normal and ring chromosome 4 by an additional FISH study. These results were confirmed by means of array-CGH showing terminal deletions on 4p16.3 (130 kb) and 4q35.2 (2.449 Mb). In the 21th week of pregnancy, no gross anomalia, except two weeks symmetric growth retardation, was present in the fetal ultrasonographic examination. According to our review of literature, this is the first prenatal case with 4p and 4q subtelomeric deletion of ring chromosome 4 without the involvement of WHS critical region. Our report describes the prenatal case with a ring chromosome 4 abnormality completely characterized by array-CGH which provided complementary data for genetic counseling of prenatal diagnosis.
Department of Medical Biology, Faculty of Medicine, Harran University, 63100 Sanliurfa, Turkey ; Department of Medical Biology and Genetics, Faculty of Medicine, Dicle University, 21280 Diyarbakir, Turkey.
Halit
H
Akbas
Department of Medical Genetics, Faculty of Medicine, Kocaeli University, 41000 Kocaeli, Turkey.
Naci
N
Cine
Department of Gynecology and Obstetrics, Faculty of Medicine, Dicle University, 21280 Diyarbakir, Turkey.
Mahmut
M
Erdemoglu
Department of Internal Medicine, Bagcılar Education and Research Hospital, 34200 Istanbul, Turkey.
Ahmet Engin
AE
Atay
Department of Medical Biology and Genetics, Faculty of Medicine, Dicle University, 21280 Diyarbakir, Turkey.
Selda
S
Simsek
Department of Medical Biology and Genetics, Faculty of Medicine, Dicle University, 21280 Diyarbakir, Turkey.
Aysegul
A
Turkyilmaz
Department of Medical Biology and Genetics, Faculty of Medicine, Dicle University, 21280 Diyarbakir, Turkey.
Mehmet
M
Fidanboy