目的　分析3号染色体p25.3p25.2 （3p25.3p25.2）片段缺失的临床表型及分子遗传学特点。方法　回顾分 析1例3p25.3p25.2染色体片段缺失患儿的临床资料，分析其临床表型及分子遗传学特征。结果　患儿，男， 1岁4个月。 宫内发育迟缓，重度矮小、全面生长发育落后、语言发育迟缓、特殊面容伴多发畸形（小头畸形、小下颌、长人中、低耳位、 双侧耳前瘘管等）、先天性十二指肠闭锁、肠旋转不良，先天性心脏病、隐睾、龟头裸露、肌张力低下、婴儿期喂养困难、睡 眠障碍、甲状腺功能减低。患儿染色体核型分析46，XY。基因芯片分析示3p25.3p25.2区域存在一段3 327 kb的杂合缺失， 共39个基因缺失。结论　3p25.3p25.2区域3 327 kb杂合缺失，致SETD5、VHL、FANCD2基因缺失导致该患儿临床表型。

Objective　To investigate the clinical phenotype and genetic characteristics of loss of heterozygosity (LOH) in chromosome fragment 3p25.3p25.2. Method　The clinical data, clinical phenotype and molecular genetic characteristics of LOH in chromosome fragment 3p25.3p25.2 in a child were analyzed retrospectively. Results　A boy, aged 1 year and 4 months old, suffered from intrauterine growth retardation, severe short stature, overall growth retardation, language retardation and special face with multiple malformations (microcephaly, head appearance deformity, small mandible, long philtrum, low ear position, bilateral preauricular fistulas, etc.). He also had congenital duodenal atresia, intestinal malrotation, congenital heart disease, cryptorchidism, glans exposure, hypotonia, feeding difficulties in infancy, sleep disorders and hypothyroidism. Chromosome karyotype of the child showed 46, XY. Chromosomal microarray analysis results demonstrated a 3327 kb heterozygous deletion in 3p25.3p25.2, a total of 39 gene deletions. Conclusion　The loss of heterozygosity of 3327 kb in 3p25.3p25.2 region resulted in the deletion of SETD5, VHL, and FANCD2 genes, which led to the clinical phenotype of this child.