62. Bất thường nhiễm sắc thể số 4 dạng vòng: Báo cáo ca bệnh và tổng quan tài liệu

Abstract

Ring chromosome 4 syndrome is a rare chromosomal disorder typically characterized by the loss of genetic material from both terminal ends of the chromosome, followed by the fusion of these ends to form a ring chromosome. The clinical manifestations of individuals with ring chromosome 4 abnormalities vary depending on the extent of genetic material loss, the proportion of cells carrying the abnormal chromosome, the stability of the ring chromosome, cell division during mitosis, or other associated chromosomal abnormalities. Common clinical features include facial dysmorphism, psychomotor developmental delay, cranial malformations, and congenital heart defects. This study reports a case of a 19 month old boy who presented with poor weight gain, facial dysmorphism, and psychomotor developmental delay. Chromosomal analysis of the patient revealed mosaicism with four abnormal cell lines, including a structural abnormality of ring chromosome 4: 46,XY,r(4)(p16q35)[40]/46,XY,dic r(4)(p16q35)[5]/91,XXYY,dic r(4)(p16q35)[4]/45,XY,-4[3]. Loss of 4pterminal and 4q terminal were identified by fluorescence in situ hybridization (FISH).