ESPE Abstracts

Entry: Rickets is a generalized metabolic bone disease manifested by the abnormal increase in osteoid tissue, defective mineralization and deformation of the epiphyseal plate, which occurs as a result of vitamin D and mineral deficiency before epiphysial fusion occurs in adolescence. Although rickets is mostly seen due to vitamin D deficiency, it can rarely be seen in vitamin D metabolism disorders and diseases that cause phosphorus loss. Clinical findings such as late closure of fontanel, delayed teething, hypotonia, rachitic rosary, harrison groove, delay in walking, gait disturbance and O/X leg deformity (genu varum/valgum) suggest rickets. Irregularity in the long bone epiphyses, bowl formation, decrease in bone density and greenstick fractures can be seen on radiography. Some systemic diseases causing bone involvement and skeletal dysplasia can be confused with rickets. Incorrect treatment can cause complications.

Material and methods: We described the striking features of two sibling cases who were considered to be differentially diagnosed with rickets with their presentation and radiological findings.

Cases: Two siblings, 3 and 1.5 years old whose parents were not consanguineous, presented with delay in walking, crooked gait, O-bain deformity, bone pain and short stature. Similarly, the father had short stature, genu varum, and bone pain, primarily X or autosomal dominant inherited hypophosphotemic rickets was considered. Ca, P, Alp, PTH and vitamin D levels were evaluated and found within normal limits. In the bone survey radiographs of both brothers, there were coxa vara, femoral bowing and increased lumbar lordosis findings in addition to the appearance compatible with rickets in the long bone metaphyses. They were followed up for short stature and bone dysmorphism until the age of 12.5 and 10.5, respectively. Growth hormone treatment was not initiated because both cases had sufficient response to growth hormone stimulation tests. In genetic evaluation, a known heterozygous pathogenic variant was detected in the COL10A1 gene, consistent with Schmid Metaphyseal Chondrodysplasia, an autosomal dominant inherited chondrodysplasia.

Conclusion: After the vitamin D prophylaxis program started in May 2005 in Turkey, the frequency of nutritional rickets decreased. For this reason, raising awareness about rare forms of rickets and hereditary bone diseases facilitates early and accurate diagnosis of patients. Therefore, the diagnosis of rickets should not only be made based on physical examination and radiological findings, but should be evaluated together with serum calcium, phosphorus and vitamin D levels.

Keywords: Short stature, rickets, vitamin D deficiency, Schmid metaphyseal chondrodysplasia, O-Bain.