■染色体异常主要在0.5-0.8%的具有发育和形态缺陷的活产婴儿中发现。近心倒位是染色体内结构重排,导致携带者染色体配子不平衡的风险。
■这里,我们报告了1例由于母体第18号染色体副中心倒位而导致第18号染色体双中心重排的患者。病人是个女孩,3岁零11个月。她因多种先天性异常被转诊,严重的智力残疾,和运动迟缓。她患有小头畸形,突出的异位缝线,synphrys,上等褶皱,telechanthus,广泛的阿拉斯,宽小柱,双侧唇腭裂,Carinatum,脐疝,pesplanus,肛门前移。她患有双侧外耳道狭窄和轻度右侧和中度左侧感音神经性听力损失。超声心动图显示继发孔型房间隔缺损,轻度三尖瓣衰竭。脑磁共振成像仅显示call体后部区域变薄。染色体分析显示46,XX,GTG和C带的dicrec(18)。通过荧光原位杂交分析确认了双中心染色体。父系核型正常46,XY,但母系染色体分析显示18号染色体有46,XX,inv(18)(q11.2?q21.3?)核型。对来自患者的外周血样品进行阵列CGH,并在18p11.32p11.21和18q11.1q11.2处显示重复,在18q21.33q23处显示缺失。患者最终核型为ARR18p11.32p11.21(64,847_15,102,598)×3,18q11.1q11.2(18,542,074_22,666,470)×3,18q21.33q23(59,784,364_78,010,032)×1。
■据我们所知,这是由于父母的18号染色体副中心倒位而导致的18号双中心染色体患者的首次报道。我们对基因型-表型相关性进行了文献综述。
UNASSIGNED: Chromosomal abnormalities are mostly found in 0.5-0.8% of live-born infants with developmental and morphological defects. Paracentric inversions are structural intrachromosomal rearrangements resulting in a risk of chromosomally unbalanced gametes in carriers.
UNASSIGNED: Herein, we report a patient with dicentric rearrangement of chromosome 18 due to maternal paracentric inversion of chromosome 18. The patient was a girl, aged 3 years and 11 months. She was referred due to multiple congenital abnormalities, severe intellectual disability, and motor retardation. She had microcephaly, prominent metopic suture, synophrys, epicanthic folds, telecanthus, wide-set alae nasi, wide columella, bilateral cleft lip and palate, pectus carinatum, umbilical hernia, pes planus, and anteriorly displaced anus. She had bilateral external auditory canal stenosis and mild right-sided and moderate left-sided sensorineural hearing loss. Echocardiography showed secundum-type atrial septal defect and mild tricuspid failure. Brain magnetic resonance imaging showed only thinning of posterior areas of the corpus callosum. Chromosome analysis showed 46,XX,dic rec(18) by GTG and C banding. Dicentric chromosome was confirmed by fluorescence in situ hybridization analysis. Paternal karyotype was normal 46,XY but maternal chromosome analysis showed a paracentric inversion in chromosome 18 with 46,XX,inv(18)(q11.2?q21.3?) karyotype. Array CGH was performed on a peripheral blood sample from the patient and showed duplication at 18p11.32p11.21 and 18q11.1q11.2, and deletion at 18q21.33q23. The patient\'s final karyotype is arr 18p11.32p11.21(64,847_15,102,598)×3,18q11.1q11.2(18,542,074_22,666,470)×3,18q21.33q23(59,784,364_78,010,032)×1.
UNASSIGNED: To the best of our knowledge, this is the first report of a patient with dicentric chromosome 18 due to a parental paracentric inversion of chromosome 18. We present the genotype-phenotype correlation with literature review.