目的 探讨软骨发育不全、致死性骨发育不良Ⅰ型等成纤维细胞生长因子受体3基因基因(fibroblast growth factor 3, FGFR3)相关性短肢发育异常胎儿X线特点。方法 取产前超声疑诊、经FGFR3基因检测确诊的6例软骨发育不全和9例致死性骨发育不良Ⅰ型引产胎儿为研究组（ACH组和TDⅠ组），65例因计划生育或其他原因引产的骨骼发育正常胎儿为对照组。3组胎儿引产后行全身整体正侧位X线检查，定性分析3组胎儿全身骨骼发育特点，定量比较分析3组胎儿坐骨切迹角度、肱骨长/宽、股骨长/宽、第一腰椎长/高、腰椎椎弓根间距比（L4/L1）、腓骨长/胫骨长等指标。结果 ACH组胎儿X线表现：6/6例为长骨干骺端膨大、火焰状、边缘不光整；5/6例长骨粗短、方形髂骨、鱼嘴状坐骨切迹。TDⅠ组胎儿X线表现：9/9例显示长骨极其短小、椎体扁平、椎间盘间距增宽、“电话接收器”状股骨、干骺端边缘不光整和喇叭口样改变、方形髂骨、鱼嘴状坐骨切迹；8/9例“电话接收器”状肱骨、巨颅。研究组坐骨切迹角度小于对照组，2组均数±标准差分别为67.9°±16.0°和109.0°±10.3°。3组胎儿肱骨长/宽、股骨长/宽、第一腰椎长/高差别具有统计学差异：依正常组、ACH组、TDⅠ组次序，肱骨和股骨有逐渐短粗的变化趋势，第一腰椎有逐渐扁平的变化趋势。3组胎儿腰椎椎弓根间距比（L4/L1）差异无统计学意义，说明ACH组和TDⅠ组胎儿腰椎椎弓根间距比（L4/L1）无病理改变。3组胎儿腓骨长/胫骨长具有统计学差异，但3组胎儿均无腓骨长于胫骨。结论 软骨发育不全和致死性骨发育不良Ⅰ型胎儿X线均表现为长骨粗短、方形髂骨、鱼嘴状坐骨切迹等，但后者X线畸形程度更重—长骨极其短小，表现更典型—“电话接收器”状股骨和肱骨、胸廓狭小、椎体扁平、椎间盘间距增宽。与儿童或成人期软骨发育不全不同，胎儿期患者并无典型腰椎椎弓根间距比（L4/L1）<1和腓骨长于胫骨等X线表现。
Objective To explore the X-ray characteristics of FGFR3 gene associated short-limb dysplasias in fetuses including achondroplasia and thanatophoric dysplasiaⅠ. Method Sixty-five induced aborted fetuses due to family plan or other reasons which had normal skeletal development were selected as control group.Six fetuses affected with achondroplasia and 9 with thanatophoric dysplasia Ⅰwhich were doubted by prenatal sonography and confirmed by FGFR3 genetic detection were regarded as study group. .Each fetus was taken a radiographic examination as a whole in frontal and lateral projection after birth. Qualitive and quantitive analysis of skeletal development were both performed in all the 3 groups. Indexes including the angle of ischial notches, humeral length to width ratio, femoral length to width ratio, the ratio of the interpedicular distances between the fourth (L4) and the first (L1) lumbar vertebrae (L4/L1 ratio), and the ratio of fibula length to tibia length were measured or calculated . Results Six fetuses affected with achondroplasia were characterized by metaphysic flaring, irregular border of metaphysis, shortened and widened long bones, square iliac wings, “fish mouth” appearance ischial notches. Nine fetuses affected withⅠwere characterized by severe shortened and widened long bones, metaphysic flaring, irregular border of metaphysis, narrow thorax, flat vertebral bodies with wide spaces between them, “telephone receiver” appearance femora and humerus, square iliac wings, “fish mouth” appearance ischial notches. Humeral length to width ratio, femoral length to width ratio, the length to height ratio of the first lumbar vertebrae showed significantly statistic difference in the three groups. According to the order of control group, achondroplasia and thanatophoric dysplasiaⅠ, the humerus and femur had the trend of growing smaller and wider while the first lumbar vertebrae growing flatter. The L4/L1 ratio showed no significantly statistic difference, which meaned no pathologic change of L4/L1 ratio in study group. The ratio of fibula length to tibia length showed significantly statistic difference but without fibula length longer than tibia length in three groups. Conclusions Genetyped achondroplasia and thanatophoric dysplasiaⅠshared common X-ray characteristics including shortened and widened long bones, square iliac wings, “fish mouth” appearance ischial notches, etc..However, the latter showed more severe and typical abnormalities: extremely shortened long bones, “telephone receiver” appearance femora and humerus, narrow thorax, flat vertebral bodies with wide spaces between them. Differentiated from children of adult patients, achondroplasia at fetal stage showed no L4/L1 ratio less than 1 or the ratio of fibula length to tibia length more than 1.
