<unk> . Leg radiographs depicting dysplastic distal femoral and proximal tibial epiphyses, and distal femoral metaphyseal broadening, cupping, irregularities (white arrows) and radiolucent areas especially medially. Note the metaphyseal line of ossification of the proximal tibias (blackarrows) and relative sparing of the tibial shafts. The changes around the knee are known as "rachitic-like changes". Lesions are bilateral and symmetrical. Exact diagnosis remains widely built on precise history taking, with the characteristic clinical and radiographic skeletal features. Genetic diagnosis is based on DNA sequencing. Because plasma COMP levels are significantly reduced in patients with COMP mutations, such as<unk> , measuring plasma COMP levels has become a reliable means of diagnosing this and pathopysiologically similar disorders. Skeletal radiography Accurate assessment of plain radiographic findings remains an important contributor to diagnosis of<unk> . It is noteworthy that vertebral radiographic abnormalities tend to resolve over time. Epiphyseal abnormalities tend to run a progressive course. Patients usually suffer early-onset arthritis of hips and knees. Many unique skeletal radiographic abnormalities of patients with<unk>  have been reported in the literature. * Together with rhizomelic limb shortening, the presence of epiphyseal-metaphyseal changes of the long bones is a distinctive radiologic feature of<unk> . * Hypoplastic capital femoral epiphyses, broad short femoral necks, coxa vara, horizontality of acetabular roof and delayed eruption of secondary ossification center of os pubis and greater trochanter. * Dysplastic/hypoplastic epiphyses especially of shoulders and around the knees. * Metaphyseal broadening, irregularity and metaphyseal line of ossification. These abnormalities that are typically encountered in proximal humerus and around the knees are collectively known as “rachitic-like changes”. * Radiographic lesions of the appendicular skeleton are typically bilateral and symmetric. * Oval shaped vertebrae with anterior beak originating and platyspondyly demonstrated on lateral radiographs of the spine. * Normal widening of the interpedicular distances caudally demonstrated on anteroposterior radiographs of the dorsolumbar region. This is an important differentiating feature between<unk>  and achondroplasia. * Odontoid hypoplasia may occur resulting in cervical instability. Differential diagnosis * Achondroplasia * Multiple epiphyseal dysplasia * Mucopolysaccharidosis * Other causes of genu valgum (knock knees) or genu varum (bow legs) such as rickets * Spondyloepiphyseal dysplasia congenita * Radiographic findings of the pelvis and hips found in Perthes disease should not be confused with<unk> . Patients with Perthes disease may present with unilateral hip affection. Besides bilateral hip affection are usually asymmetric. In contrast patients with<unk>  typically exhibit bilateral and symmetric hip involvement.
Pseudoachondroplasia
Achondroplasia
Rachischisis
Gastroschisis
Diaschisis
Omphalocele
Cranioschisis
Hypospadias