Spondyloepiphyseal dysplasia type Stanescu (SED‐S) is a very rare type II collagenopathy. We describe an 8‐year‐old boy who presented with short trunk, C2‐C3 vertebral fusion, hand, foot, leg and thigh pain, stiffness and limited joint mobility, and waddling gait. Radiographs showed platyspondyly with anterior wedging and endplate irregularities, broad femoral necks, and large epiphyses and epiphyseal equivalents. Differential diagnosis included progressive pseudorheumatoid dysplasia and SED‐S. A skeletal dysplasia custom‐designed NGS panel was performed and the heterozygous pathogenic variant c.620G>A; p.(Gly207Glu) in COL2A1 was detected, establishing the diagnosis of SED‐S. Vertebral fusions, observed in our patient, have not been previously described in this dysplasia. This variant has not been previously associated with SED‐S, but was reported in two other families with spondyloepiphyseal dysplasia. Thus, this case expands the clinical and mutational spectrum of SED‐S and demonstrates that SED‐S significantly overlaps with other skeletal dysplasias.

中文翻译：

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Stanescu型脊椎干phy发育不良：扩大了一种非常罕见的II型胶原病的临床和分子谱。

Stanescu型脊柱干phy发育不良（SED‐S）是一种非常罕见的II型胶原病。我们描述了一个八岁男孩，他的躯干短，C2-C3椎骨融合，手，脚，腿和大腿疼痛，僵硬，关节活动受限，步态蹒跚。X线片显示肩前突和终板不规则，股骨颈宽大，骨epi及骨phy相当。鉴别诊断包括进行性假性风湿性发育不良和SED-S。进行了骨骼发育异常定制设计的NGS面板，杂合致病性变体c.620G> A；p。（Gly207Glu）在COL2A1中被检测到，从而确定了SED‐S的诊断。在我们的患者中观察到的椎骨融合术尚未在这种发育不良中进行过描述。该变体以前并未与SED‐S相关，但在另外两个患有脊柱干phy发育不良的家族中已有报道。因此，该病例扩大了SED‐S的临床和突变谱，并证明SED‐S与其他骨骼发育异常明显重叠。