Mutations in kelch-like 3 and cullin 3 cause hypertension and electrolyte abnormalities.

Hypertension affects one billion people and is a principal reversible risk factor for cardiovascular disease. Pseudohypoaldosteronism type II (PHAII), a rare Mendelian syndrome featuring hypertension, hyperkalaemia and metabolic acidosis, has revealed previously unrecognized physiology orchestrating the balance between renal salt reabsorption and K(+) and H(+) excretion. Here we used exome sequencing to identify mutations in kelch-like 3 (KLHL3) or cullin 3 (CUL3) in PHAII patients from 41 unrelated families. KLHL3 mutations are either recessive or dominant, whereas CUL3 mutations are dominant and predominantly de novo. CUL3 and BTB-domain-containing kelch proteins such as KLHL3 are components of cullin-RING E3 ligase complexes that ubiquitinate substrates bound to kelch propeller domains. Dominant KLHL3 mutations are clustered in short segments within the kelch propeller and BTB domains implicated in substrate and cullin binding, respectively. Diverse CUL3 mutations all result in skipping of exon 9, producing an in-frame deletion. Because dominant KLHL3 and CUL3 mutations both phenocopy recessive loss-of-function KLHL3 mutations, they may abrogate ubiquitination of KLHL3 substrates. Disease features are reversed by thiazide diuretics, which inhibit the Na-Cl cotransporter in the distal nephron of the kidney; KLHL3 and CUL3 are expressed in this location, suggesting a mechanistic link between KLHL3 and CUL3 mutations, increased Na-Cl reabsorption, and disease pathogenesis. These findings demonstrate the utility of exome sequencing in disease gene identification despite the combined complexities of locus heterogeneity, mixed models of transmission and frequent de novo mutation, and establish a fundamental role for KLHL3 and CUL3 in blood pressure, K(+) and pH homeostasis.

ZOLEDRONIC ACID THERAPY OF PATIENTS WITH PAGET DISEASE OF BONE RESISTANT TO OR WITH UNSUSTAINED REMISSION FOLLOWING PRIOR BISPHOSPHONATE THERAPY.

OBJECTIVE: To evaluate the effect of zoledronic acid (ZA) in patients with Paget disease (PD) who had not had a biochemical remission with prior bisphosphonate therapy or had a remission ≤12 months. METHODS: The effects of ZA therapy were studied in 14 patients aged 54 to 90. Serum alkaline phosphatase (ALP) levels were elevated to at least 40% above the normal reference range, and glomerular filtration rates (GFRs) were ≥40 mL/minute. ZA (5 mg) was infused over 15 minutes. ALP and urine N-telopeptide/creatinine (NTx/Cr) were obtained before therapy and at 3, 6, 9, and 12 months, and thereafter at 4-month intervals. RESULTS: At baseline, ALP ranged from 141 to 1,009 U/L. In 13 patients, ALP fell to normal following ZA administration. Remissions occurred in 9 patients who had not previously had a remission. Remissions varied from 12 to 60 months and were more prolonged in 4 patients with prior remissions ≤12 months. ZA failed to induce a remission in 1 patient. Ten to 12 days after therapy in 3 asymptomatic patients, serum calcium levels fell to 7.9, 8, and 8.3 mg/dL. Other than flu-like symptoms in 3 patients after ZA infusion, there were no other adverse effects. CONCLUSION: Therapy with ZA induced remissions in 13/14 patients and induced more prolonged remissions in patients who previously had remissions ≤12 months. The lack of remission in 1 patient despite 2 courses of therapy is evidence of a continuing therapeutic challenge for some patients with a more resistant form of PD.

Ten years' experience with alendronate for osteoporosis in postmenopausal women.

BACKGROUND: Antiresorptive agents are widely used to treat osteoporosis. We report the results of a multinational randomized, double-blind study, in which postmenopausal women with osteoporosis were treated with alendronate for up to 10 years. METHODS: The initial three-year phase of the study compared three daily doses of alendronate with placebo. Women in the original placebo group received alendronate in years 4 and 5 and then were discharged. Women in the original active-treatment groups continued to receive alendronate during the initial extension (years 4 and 5). In two further extensions (years 6 and 7, and 8 through 10), women who had received 5 mg or 10 mg of alendronate daily continued on the same treatment. Women in the discontinuation group received 20 mg of alendronate daily for two years and 5 mg daily in years 3, 4, and 5, followed by five years of placebo. Randomized group assignments and blinding were maintained throughout the 10 years. We report results for the 247 women who participated in all four phases of the study. RESULTS: Treatment with 10 mg of alendronate daily for 10 years produced mean increases in bone mineral density of 13.7 percent at the lumbar spine (95 percent confidence interval, 12.0 to 15.5 percent), 10.3 percent at the trochanter (95 percent confidence interval, 8.1 to 12.4 percent), 5.4 percent at the femoral neck (95 percent confidence interval, 3.5 to 7.4 percent), and 6.7 percent at the total proximal femur (95 percent confidence interval, 4.4 to 9.1 percent) as compared with base-line values; smaller gains occurred in the group given 5 mg daily. The discontinuation of alendronate resulted in a gradual loss of effect, as measured by bone density and biochemical markers of bone remodeling. Safety data, including fractures and stature, did not suggest that prolonged treatment resulted in any loss of benefit. CONCLUSIONS: The therapeutic effects of alendronate were sustained, and the drug was well tolerated over a 10-year period. The discontinuation of alendronate resulted in the gradual loss of its effects.

Normocalcemic primary hyperparathyroidism associated with progressive cortical bone loss - A case report.

The existence of normocalcemic primary hyperparathyroidism (NPHP) was acknowledged at the Third and Fourth International Proceedings on primary hyperparathyroidism PHPT but data relating to its clinical presentation, natural history, and skeletal status were limited and there was no information nor guidelines as to definitive therapy. Herein are reported biochemical, hormonal, and densitometry data in a postmenopausal woman seen initially for osteoporosis who was found to have increased serum PTH levels and normal serum total and ionized calcium levels without evidence of secondary hyperparathyroidism. Over a seven year period, the patient exhibited continuing preferential cortical bone loss at the one-third site of the radius in the face of relatively stable readings at the lumbar spine and hip that led to a subtotal parathyroidectomy for parathyroid hyperplasia with resultant normalization of serum PTH.

Skeletal Fluorosis Due To Inhalation Abuse of a Difluoroethane-Containing Computer Cleaner.

Skeletal fluorosis (SF) is endemic in many countries and millions of people are affected worldwide, whereas in the United States SF is rare with occasional descriptions of unique cases. We report a 28-year-old American man who was healthy until 2 years earlier when he gradually experienced difficulty walking and an abnormal gait, left hip pain, loss of mobility in his right wrist and forearm, and progressive deformities including enlargement of the digits of both hands. Dual-energy X-ray absorptiometry (DXA) of his lumbar spine, femoral neck, total hip, and the one-third forearm revealed bone mineral density (BMD) Z-scores of +6.2, +4.8, +3.0, and -0.2, respectively. Serum, urine, and bone fluoride levels were all elevated and ultimately explained by chronic sniffing abuse of a computer cleaner containing 1,1-difluoroethane. Our findings reflect SF due to the unusual cause of inhalation abuse of difluoroethane. Because this practice seems widespread, particularly in the young, there may be many more such cases. © 2016 American Society for Bone and Mineral Research.

Importance of early diagnosis and treatment of osteoporosis to prevent fractures.

Osteoporosis affects about 10 million individuals in the United States, a number that is expected to increase substantially in coming decades as the elderly population burgeons. The chief debilitating consequence of osteoporosis, fracture, will affect about half the women and a third of the men in their lifetime, posing a daunting challenge to managed healthcare systems in terms of delivering optimal care and restraining cost. By encouraging optimal postfracture follow-up care and identifying those members at higher risk for fracture and in need of prompt treatment, managed care organizations can enhance the cost-effective management of osteoporosis, dampening downstream costs. This manuscript reviews the pathophysiology of osteoporosis, examines issues related to the diagnosis of osteoporosis, especially the role of bone mineral density measurement, and focuses on the impact of various treatment options in reducing fracture risk. Early assessment and treatment emerge as medically prudent steps in reducing the risk for osteoporosis-related fracture.

Effect of zoledronic acid on serum calcium in Paget's disease patients after educational strategies to improve calcium and vitamin D supplementation.

OBJECTIVE: Bisphosphonates are the most effective therapeutic agents in patients with Paget's disease of bone. As a result of their inhibition of osteoclastic activity, hypocalcemia of variable frequency and severity following intravenous bisphosphonate therapy has been reported. The present study assessed the effect of physician and patient education on adequate supplementation of calcium and vitamin D to reduce the potential risk of developing hypocalcemia following infusion of 5 mg zoledronic acid. METHODS: This was an open-label, multicenter, controlled registry trial in which patients with Paget's disease were treated with a single intravenous infusion of zoledronic acid. Physicians were provided with educational materials focusing on optimization of calcium and vitamin D supplementation following zoledronic infusion that they used to educate their patients. The primary safety variable was the percentage of patients with serum calcium level <2.07mmol/l 9-11 days after zoledronic acid infusion. RESULTS: A total of 75 patients were evaluable in the post dose hypocalcemia safety analysis. Of these, only 1 patient had treatment-emergent hypocalcemia, with a serum calcium level of 1.92 mmol/l 4 days following therapy. Hypocalcemia-related symptoms were not reported in this patient and the serum calcium returned to normal range at 2.17 mmol/l within 1 week on oral calcium supplementation. CONCLUSIONS: These results suggest that, with optimization of calcium and vitamin D supplementation by physician and patient education, hypocalcemia is an infrequent occurrence following zoledronic acid infusion.

An interesting case of peripheral vascular disease, vascular reperfusion, and subsequent development of pain due to Paget's disease of bone.

OBJECTIVE: To present a case of Paget's disease of bone that was unmasked after vascular reperfusion. METHODS: In this case study, we review the presentation, evaluation, diagnosis, and management of a patient with Paget's disease and peripheral vascular disease. RESULTS: A 79-year-old-woman with a history of coronary artery heart disease and recent finding of a T5 compression fracture was hospitalized for evaluation of right lower extremity claudication. Angiography demonstrated a focal complete occlusion of the distal right femoral and popliteal arteries. A self-expanding stent was placed in the distal femoral and popliteal arteries. Approximately 48 hours after the procedure, the patient developed severe, right lower leg pain. On endocrine evaluation, the patient was found to have clinical signs suggesting Paget's disease of bone, which was subsequently confirmed by imaging. CONCLUSION: This patient's development of severe pain following reperfusion of distal femoral and popliteal arteries is in keeping with the known and aforementioned hypervascularity of pagetic bone. The finding of increased warmth over an area of skeletal deformation should always raise the possibility of Paget's disease of bone.

Therapy with zoledronic acid, 5 mg, for a patient with Paget disease of bone.

OBJECTIVE: To describe the effects of an infusion of zoledronic acid in a patient with Paget disease of bone (PD) who had been treated unsuccessfully with several other bisphosphonates. METHODS: The patient's treatment history is described, and his response to various bisphosphonates, including zoledronic acid, is discussed. RESULTS: The patient was a 61-year-old man when a diagnosis of PD was made on the basis of an elevated serum alkaline phosphatase (ALP) level of 391 U/L (reference range, 45 to 135). Pagetic bone changes were noted on bone scan and x-ray examinations. Treatment with etidronate had no effect on ALP levels. This intervention was followed by 2 courses of intravenous therapy with pamidronate, which decreased ALP levels by 57% and 55% without inducing a remission. Subsequent oral treatment with alendronate and then risedronate yielded unsustained biochemical remissions of 6 months each. Most recently, therapy with an infusion of 5 mg of zoledronic acid induced a remission that is thus far 20 months in duration. With this therapy, the patient has experienced no side effects, and he has noted a decrease in bone pain. CONCLUSION: This case study shows that a patient with PD who received successive treatments with several bisphosphonates with inadequate responses or only brief remissions was more effectively treated with a single 5-mg infusion of zoledronic acid. This patient's therapeutic responses illustrate the relative efficacy of available bisphosphonates and the potential for longer-lasting remissions with zoledronic acid in patients with PD.

Paraganglioma-Like Adenomas of the Thyroid (PLAT): Incidental Lesions with Unusual Features in a Patient with Nodular Goiter.

We discovered two well-demarcated nodules incidentally in a thyroid removed because of a nodular goiter. Histologically, the nodules showed a pattern of paraganglioma or so-called paraganglioma-like adenoma of the thyroid (PLAT), with lobules of polygonal and oval cells in a vascular stroma, but the immunohistochemical markers typical of paraganglioma, including chromogranin, synaptophysin, Leu 7 and 5-100, and thyroglobulin, characteristic of PLAT, were negative in the tumor cells. C-cell markers calcitonin and somatostatin were also negative. Stain for neuron-specific enolase (NSE), however, showed a distinctive pattern of reactivity within cells at the periphery of the lobules, whereas all tumor cells stained positively for keratins. Stain for carcinoembryonic antigen showed a focal interstitial pattern that corresponded to small intercellular spaces filled by microvilli identified ultrastructurally. This pattern of immunohistochemical staining has not been previously described in paraganglioma or in PLAT, and may have implications about the origin and nature of these controversial entities.