Spondylometaphyseal dysplasia is an extremely rare genetic disorder of the bones, primarily involving the axial skeleton, with short stature, abnormally shaped vertebrae, and scoliosis being the most common features. The diagnosis may be difficult to attain, but family history is one of the most important steps in workup, in addition to the radiographic identification of skeletal changes.
The clinical presentation of patients with spondylometaphyseal dysplasia (SMD) starts as early as infancy and involves various skeletal abnormalities, but the axial skeleton - the rib cage and the spine, and the metaphyses of femoral bones, but also the iliac bones are principally affected . Flattened vertebral bodies (platyspondyly), congenital scoliosis, dysplasia of the ribs, iliac and proximal femur (frequently ending in development of coxa vara) are main manifestations of SMD  , followed by postnatal growth failure and short stature that is evident from early childhood, progressive lower-limb bowing, and a fragmented appearance of metaphyses (known as "corner fractures") . Moreover, impaired growth causes hypoplasia of the rib cage due to shortening of the ribs, which can create respiratory problems of varying severity, but an increased susceptibility to infections is frequently documented . In some patients, retinal changes, such as retinitis pigmentosa, pigmentary retinal degeneration or cone-rod dystrophy, appear in early childhood and can lead to visual impairment, mainly affecting visual acuity  .
Having in mind the fact that the vast majority of cases appear in a familial fashion, a detailed patient history can reveal the presence of symptoms in siblings or first-degree relatives, thus confirming clinical suspicion toward inherited diseases. In fact, parental consanguinity has been reported in some cases . A carefully performed physical examination is the next step in workup, which should note visual impairment and signs of reduced growth and scoliosis, as well as thoracic hypoplasia. Imaging studies, primarily in the form of radiography, are used to describe the changes seen in SMD, most important being cupped and flared anterior end of ribs, mild spondylar dysplasia, serrated iliac crests, and metaphyseal dysplasia involving the proximal femur  . Although the genetic basis of the disease remains incompletely understood, whole-genome sequencing has revealed mutations in chromosome 21 open reading frame 2 (C21orf2) and choline phosphate cytidyltransferase A (PCYT1A) genes, suggesting that their detection may be helpful in distinguishing the diagnosis from more than 40 other skeletal disorder groups that have a similar clinical presentation and background  . Other reports, however, have evaluated the presence of mutations in the collagen 2 alpha 1 (COL2A1) gene and parathyroid hormone 1 receptor (PTH1R) , but clear genetic markers are yet to be defined, and the diagnosis frequently rests on radiographic and clinical criteria. Magnetic resonance imaging (MRI) can be used for detecting spinal abnormalities. Moreover, other imaging techniques like hip arthrography, computed tomography (CT) may also be employed for the diagnosis of the disease.