Calcification of Entheses Associated with X-Linked Hypophosphatemic Osteomalacia

Abstract

We undertook a retrospective analysis of 26 patients with X-linked hypophosphatemic osteomalacia (or rickets), whose ages ranged from 1 to 62 years and who were from 11 different kindreds, to determine the prevalence and clinical characteristics of a unique disorder of the entheses (tendons, ligaments, and joint capsules). We found a generalized involvement of the entheses, with exuberant calcification of tendon and ligament insertions and of joint capsules, in 69 per cent of the subjects. The prevalence and extent of disease increased with age but were not correlated with sex. Commonly affected sites included the hand and sacroiliac joints. Histologic evaluation in a selected patient revealed intratendinous lamellar bone but no inflammatory cells. Our observations indicate that this disorder is an integral part of X-linked hypophosphatemic osteomalacia and exhibits clinical, radiographic, and histologic characteristics that differentiate it from degenerative disorders of these tissues and seronegative spondyloarthropathies.

Assessment of Bone Quality by Quantitative Ultrasound of Proximal Phalanges of the Hand and Fracture Rate in Children and Adolescents with Bone and Mineral Disorders

“…Lumbar BMDarea and lumbar BMDvolume values of patients were compared with sex-and age-reference values by using those reported by Boot et al (24), which were obtained by the same DXA machinery equipped with the same software as we used. In all patients with X-linked hypophosphatemic rickets radial BMD by single-photon absorptiometry instead of lumbar BMD was measured because they usually have reduced appendicular BMD independent of treatment (25)(26)(27) and increased axial BMD (26,27) caused by overabundance of partially mineralized osteoid (26), or a high prevalence of spinal osteosclerosis and enthesopathy (27,28). The radial BMD values were compared with sex-and age-reference values by using our own normative data (29).…”

Enthesopathy as the presenting feature of X-linked hypophosphatemia: A case report

“…It is not related to the severity of the biochemical changes, which in this case were so minimal that the diagnosis could not have been established without the family history; nor is it associated with the presence of osteomalacia or its treatment (Polisson et al 1985). The enthesopathy may be entirely symptomless, as in this case, but may contribute to the high incidence of arthrosis which has been noted in XLH (Hardy et al 1989).…”

“…In a study of 26 patients Polisson et al (1985) found two thirds to be affected, the incidence increasing with age from none under the age of 10 to 100 percent in the over-forties. A similar incidence was found by Hardy et al (1989) who found that women had a slightly higher incidence than men.…”

Radiologic Vignette

“…This is most notable at the sacroiliac joints, where widening or fusion may suggest early-or late-stage inflammatory sacroiliitis (1 1). Subchondral bone erosions, however, are not observed (9). In the spine, osteopenia is not prevalent, and the classic "rugger jersey" finding most characteristically seen in renal osteodystrophy is an uncommon radiographic feature (12).…”