Identification of autosomal supernumerary chromosome markers (SMCs) by fluorescent in situ hybridization (FISH).
Identification of autosomal supernumerary chromosome markers (SMCs) by fluorescent in situ hybridization (FISH).
复制标题
通过荧光原位杂交 (FISH) 鉴定常染色体多生染色体标记 (SMC)。
作者：
A. Kolialexi;S. Kitsiou;H. Fryssira;C. Sofocleous;E. Kouvidi;G. Tsangaris;K. Salavoura;A. Mavrou
多余标记染色体（SMCs）是一种罕见的染色体异常，导致特定基因组区域的部分三体，具有特征性表型效应。本文报告26例常染色体SMCs。在8天至15岁的儿童中，因各种先天性异常和发育迟缓而进行遗传评估的儿童中，产前鉴定了4例，产后鉴定了22例。在26例中，22例是新发的，2例是家族性的，另外2例是11例；在母亲中发现22个反向易位。只有1例患者SMC呈镶嵌状。为了确定SMCs的染色体起源，使用全染色体涂料（WCP）探针进行了序列荧光原位杂交研究（FISH）。其中16份来自第15号染色体，5份来自18p同工染色体，1份来自22号染色体，但均未包含diggeorge / VCFS临界区。在两个例子中，SMCs是13号染色体的衍生物，在两个例子中，SMCs是11号染色体的产物；22母系易位，含有11号和22号染色体的物质。对两名SMC[15]患者的分子研究发现了三个SNRPN基因拷贝，但通过甲基化特异性PCR排除了两名患者因可能的印迹而诊断为PW/AS。FISH和分子研究极大地促进了标记染色体的表征。随着越来越多的SMCs被分类，可以更好地进行遗传咨询和风险评估。
Supernumerary marker chromosomes (SMCs) are rare chromosomal abnormalities resulting in partial trisomy of specific genomic regions with characteristic phenotypic effects. Twenty six cases with autosomal SMCs are reported. Four were identified prenatally and 22 postnatally in children, aged from 8 days to 15 years, who were referred for genetic evaluation because of various congenital anomalies and developmental delay. In 22 of the 26 cases, the SMCs were de novo, in two they were familial and in another two a 11;22 reciprocal translocation was revealed in the mothers. In only one patient was the SMC present in a mosaic form. Sequential fluorescent in situ hybridization studies (FISH) using Whole Chromosome Paint (WCP) probes were performed in order to determine the chromosomal origin of the SMCs. Sixteen of them originated from chromosome 15, five were shown to be an isochromosome 18p and one was derived from chromosome 22, but did not contain the DiGeorge/ VCFS critical region. In two instances, the SMCs were derivatives of chromosome 13 and in two the SMCs resulted from a 11;22 maternal translocation and contained material from both chromosomes 11 and 22. Molecular investigation of two of the patients with an SMC[15] revealed three copies of the SNRPN gene, but the diagnosis of PW/AS due to possible imprinting was excluded in both patients by a methylation-specific PCR. FISH and molecular studies have greatly facilitated the characterization of marker chromosomes. As more SMCs are classified, better genetic counseling and risk evaluation can be achieved.