Bone mineral status and metabolism in patients with Williams-Beuren syndrome

Efficacy of denosumab therapy for a 12-year-old female patient with Williams syndrome with osteoporosis and history of fractures: a case report

Background

A decrease in bone mineral density is common in patients with Williams syndrome. However, appropriate management for osteoporosis in Williams syndrome patients has not been established. We report the case of a 12-year-old female patient with Williams syndrome, who underwent denosumab treatment for osteoporosis.

Case presentation

A 12-year-old Japanese female patient with Williams syndrome was shown to have very low bone mineral density. Bone mineral density was evaluated before treatment and at 5, 9, 17, 23, and 29 months of treatment by dual-energy X-ray absorptiometry. After denosumab therapy for 29 months, lumbar and total hip bone mineral density values had increased by 51.6% and 37.6%, respectively. No new fractures occurred during the observation period.

Conclusions

To the best of our knowledge, this is the first experience with denosumab treatment in Williams syndrome patients with osteoporosis. Based on our findings, denosumab may be an effective treatment option for Williams syndrome patients with osteoporosis.

Bone involvement and mineral metabolism in Williams' syndrome

CONTEXT

The previous studies suggested a possible increased risk of hypercalcaemia and reduced bone mineral density (BMD) in Williams' syndrome (WS). However, an extensive study regarding bone metabolism has never been performed.

OBJECTIVE

To investigate bone health in young adults with WS.

DESIGN

Cross-sectional study.

SETTINGS

Endocrinology and Metabolic Diseases and Medical Genetic Units.

PATIENTS

29 WS young adults and 29 age- and sex-matched controls.

MAIN OUTCOME MEASURES

In all subjects, calcium, phosphorus, bone alkaline phosphatase (bALP), parathyroid hormone (PTH), 25-hydroxyvitamin D (25OHVitD), osteocalcin (OC), carboxyterminal cross-linking telopeptide of type I collagen (CTX), 24-h urinary calcium and phosphorus, femoral-neck (FN) and lumbar-spine (LS) BMD and vertebral fractures (VFx) were assessed. In 19 patients, serum fibroblast growth factor-23 (FGF23) levels were measured.

RESULTS

WS patients showed lower phosphorus (3.1 ± 0.7 vs 3.8 ± 0.5 mg/dL, p = 0.0001) and TmP/GFR (0.81 ± 0.32 vs 1.06 ± 0.25 mmol/L, p = 0.001), and an increased prevalence (p = 0.005) of hypophosphoremia (34.5 vs 3.4%) and reduced TmP/GFR (37.9 vs 3.4%). Moreover, bALP (26.3 ± 8.5 vs 35.0 ± 8.0 U/L), PTH (24.5 ± 12.6 vs 33.7 ± 10.8 pg/mL), OC (19.4 ± 5.3 vs 24.5 ± 8.7 ng/mL), and FN-BMD (- 0.51 ± 0.32 vs 0.36 ± 0.32) were significantly lower (p < 0.05), while CTX significantly higher (401.2 ± 169.3 vs 322.3 ± 122.4 pg/mL, p < 0.05). Serum and urinary calcium and 25OHVitD levels, LS-BMD and VFx prevalence were comparable. No cases of hypercalcemia and suppressed FGF23 were documented. Patients with low vs normal phosphorus and low vs normal TmP/GFR showed comparable FGF23 levels. FGF23 did not correlate with phosphorus and TmP/GFR values.

CONCLUSIONS

Adult WS patients have reduced TmP/GFR, inappropriately normal FGF23 levels and an uncoupled bone turnover with low femoral BMD.

Glucose and lipid metabolism, bone density, and body composition in individuals with Williams syndrome

OBJECTIVE

We assessed body composition, bone mineral density (BMD), glucose and lipids in Williams syndrome (WS), a rare microdeletion disorder.

DESIGN

Individuals with WS had outpatient assessment at Massachusetts General Hospital. Controls were selected from the National Health and Nutrition Examination Survey (NHANES 2005-2006).

PATIENTS

A total of 22 individuals with WS, each matched by age, sex and race to four NHANES controls.

MEASUREMENTS

Blood sampling, oral glucose tolerance test, dual-energy X-ray absorptiometry scan.

RESULTS

WS and control groups were 59% female and 29 ± 8 years old. Compared to controls, individuals with WS were shorter but had similar body weight, with more fat and less lean mass. Per cent body fat was higher in WS even after adjusting for BMI (+2.1% [95% CI 0.4, 3.9%]). Four WS patients had abnormal lower extremity fat accumulation resembling lipedema. HbA1c (+0.5% [0.2, 0.7]) and 2-hour glucose (+68 mg/dL [44, 93]) were higher in WS vs controls, differences which persisted after adjusting for BMI. Fasting glucose was comparable between groups. LDL (-18 mg/dL [-35, -2]) and triglycerides (-45 mg/dL [-87, -2]) were significantly lower in WS. Whole-body BMD was significantly lower (-0.15 g/cm² [-0.20, -0.11]) in WS, and this remained true controlling for height (-0.06 g/cm² [-0.11, -0.02]). Vitamin D was <30 ng/mL in 81% of those with WS.

CONCLUSIONS

On average, adults with WS have increased fat, decreased lean mass, impaired glucose homeostasis and reduced BMD. Clinical efforts to build muscle and bone mass, and to ensure vitamin D sufficiency, are warranted. Genotype-phenotype research efforts are also warranted.

A rare association of central hypothyroidism and adrenal insufficiency in a boy with Williams-Beuren syndrome

Primary hypothyroidism related to morphological and volumetric abnormalities of the thyroid gland is one of the commonest of several endocrine dysfunctions in Williams-Beuren syndrome (WBS). We report a 10-month-old boy with WBS who presented with central hypothyroidism. During the neonatal period, he had prolonged jaundice, feeding difficulties and episodes of colic that continued during early infancy. Additionally, there was slowing of growth and mild developmental delay. He underwent surgical repair for supravalvular aortic stenosis at 6 months of age. An evaluation done to exclude cortisol deficiency before initiating levothyroxine lead to the detection of secondary adrenal insufficiency, unreported previously in WBS. In addition, insulin-like growth factor-1 (IGF-1) and IGF-binding protein-3 levels were low. This report of hypopituitarism in WBS indicates a need for complete evaluation of pituitary dysfunction in children with WBS.