Treatment of Hypophosphatemic Rickets with Phosphate and Active Vitamin D in Japan: A Questionnaire-based Survey

Dissociation of clinical, laboratory, and bone biopsy findings in adult X-linked hypophosphatemia: a case report

X‑linked hypophosphatemia (XLH) is a phosphate wasting disorder. Typical serum constellations include low serum phosphate as well as high alkaline phosphatase (ALP) and fibroblast growth factor 23 (FGF-23 ) levels. Adult XLH patients usually suffer from (pseudo)fractures, enthesopathies, impaired mobility, and osteoarthritis. We report the case of a middle-aged woman with clinically mild disease, relatively balanced laboratory values, but bone non-healing of the femur post-surgery. Transiliac bone biopsy revealed pronounced osteomalacia and severe deterioration of bone microstructure. Due to the lack of XLH-typical symptoms, the patient was not substituted with calcitriol and phosphate in adulthood. Thus, laboratory findings and radiological examinations do not necessarily reflect bone metabolism in XLH. Bone biopsies should be considered in unclear cases or prior to surgery in adults with XLH.

The Frequency of Clinical Manifestations of Hypophosphatemic Rickets in Patients with Therapeutic Strategies

The aim of this study was to evaluate the frequency of clinical manifestations of various types of rickets in patients could be effective in therapeutic strategies. A total of eleven child patients (7 females and 4 males) were included in the present study. The patients were admitted to the hospital with hypophosphatemic rickets. In our study, the age at the time of diagnosis ranged from 1 to15 years. Mean age of first presentations at final diagnosis was determined to be 5.5 an 2 years, respectively. Five patients out of 11 patients had showed significant history of vitamin D3 resistance. Family history of similar skeletal problems was reported to be positive in six patients. Furthermore, there were seven relative marriages in parents. Mean value of Gomez index has been revealed as 64%. Mean serum phosphate level was detected as 2.9 mg/dL, that this level in males (2.2 mg/dL) was significantly less than females (3.4 mg/dL) (P=0.5). Mean serum alkaline phosphatase activity was reached 913 IU/L. Alkaline phosphatase activity in women (1075 IU/L) was significantly lower than that of men (750 IU/L), (P=0.5). Definitive treatment with oral phosphate and vitamin D3 can prevent complications of the disease and the side effects of unconventional treatments.

Magnetic Resonance Imaging Features as Surrogate Markers of X-Linked Hypophosphatemic Rickets Activity

OBJECTIVE

X-linked hypophosphatemic rickets (XLH) is the most common form of inheritable rickets. Rickets treatment is monitored by assessing alkaline phosphatase (ALP) levels, clinical features, and radiographs. Our objectives were to describe the magnetic resonance imaging (MRI) features of XLH and to assess correlations with disease activity.

STUDY DESIGN

Twenty-seven XLH patients (median age 9.2 years) were included in this prospective single-center observational study. XLH activity was assessed using height, leg bowing, dental abscess history, and serum ALP levels. We looked for correlations between MRI features and markers of disease activity.

RESULTS

On MRI, the median maximum width of the physis was 5.6 mm (range 4.8-7.8; normal <1.5), being >1.5 mm in all of the patients. The appearance of the zone of provisional calcification was abnormal on 21 MRI images (78%), Harris lines were present on 24 (89%), and bone marrow signal abnormalities were present on 16 (59%). ALP levels correlated with the maximum physeal widening and with the transverse extent of the widening.

CONCLUSIONS

MRI of the knee provides precise rickets patterns that are correlated with ALP, an established biochemical marker of the disease, avoiding X-ray exposure and providing surrogate quantitative markers of disease activity.