Calcium Pyrophosphate Crystal Deposition in a Cohort of 57 Patients with Gitelman Syndrome

Updates in Deposition Arthritis Other Than Gout

This article focuses on updates in calcium pyrophosphate deposition disease (CPPD) and basic calcium phosphate deposition (BCPD), highlighting recent advances in imaging and the understanding of these conditions. It explores their clinical presentations, crystal formation mechanisms, and diagnostic challenges. CPPD and BCPD are often underrecognized causes of arthritis, and recent imaging diagnostic criteria are presented.

Case Report: Familial hypocalciuric hypercalcemia type 1 with a novel mutation combined with Gitelman syndrome and a review of the literature

Introduction

Familial hypocalciuric hypercalcemia (FHH) is an autosomal dominant disorder caused by an inactivating mutation in the CASR gene, while Gitelman syndrome (GS) is an autosomal recessive renal tubular disorder resulting from a pathogenic mutation in the SLC12A3 gene. Both genetic disorders are relatively rare. This report presents a patient with both FHH and GS, exhibiting unique clinical and genetic complexities.

Case summary

We report a case of a 69-year-old Asian female patient who had previously presented to the hospital on multiple occasions with complaints of joint stiffness, fatigue, dizziness, or other symptoms. The patient was readmitted to the hospital at the age of 66, presenting with the following clinical findings: hypocalciuria, hypercalcemia, normal or mildly elevated parathyroid hormone (PTH) levels, hypokalemia, hypomagnesemia, hypophosphatemia, normal blood pressure, chondrocalcinosis (CC), and diabetes mellitus. Our careful analysis suggested that the patient might have the co-occurrence of GS and FHH. Genetic testing revealed a novel heterozygous CASR p.Tyr161* mutation and a homozygous SLC12A3 p.Thr60Met mutation, which ultimately confirmed the diagnosis of familial hypocalciuric hypercalcemia type 1 (FHH1) combined with GS.

Conclusion

For the first time, we report a case of FHH combined with GS. The novel CASR mutation in this patient expands the variant spectrum of FHH, provides new genetic evidence for its pathogenesis, and underscores the importance of genetic counseling for consanguineous families. This case also suggests a potential association between FHH and CC, the mechanism of which warrants further investigation. In addition, this report highlights possible potential interactions between FHH and GS. Clinically, hypokalemia and hypomagnesemia associated with GS are more detrimental than hypercalcemia linked to FHH and should be prioritized in management. Finally, genetic testing and molecular diagnostics are crucial for pediatric and adolescent populations with FHH and/or GS, and further studies are needed to clarify the genotypic and phenotypic relationships between FHH and GS comorbidities.

Features Associated With Different Inflammatory Phenotypes of Calcium Pyrophosphate Deposition Disease: A Study Using Data From the International American College of Rheumatology/EULAR Calcium Pyrophosphate Deposition Classification Criteria Cohort

OBJECTIVE

The study objective was to examine the disease, demographic, and imaging features associated with different inflammatory phenotypes of calcium pyrophosphate deposition (CPPD) disease, ie, recurrent acute calcium pyrophosphate (CPP) crystal arthritis, chronic CPP crystal inflammatory arthritis, and crowned dens syndrome (CDS).

METHODS

Data from an international cohort (assembled from 25 sites in 7 countries for the development and validation of the 2023 CPPD classification criteria from the American College of Rheumatology/EULAR) that met the criteria were included. Three cross-sectional studies were conducted to determine the phenotypic characteristics of recurrent acute CPP crystal arthritis, chronic CPP crystal inflammatory arthritis, and CDS. Multivariable logistic regression analysis was used to calculate adjusted odds ratio (aOR) and 95% confidence interval (CI) to examine the association between potential risk factors and the inflammatory phenotype.

RESULTS

Among the 618 people included (56% female; mean age [standard deviation] 74.0 [11.9] years), 602 (97.4%) had experienced acute CPP crystal arthritis, 332 (53.7%) had recurrent acute arthritis, 158 (25.6%) had persistent inflammatory arthritis, and 45 (7.3%) had had CDS. Recurrent acute CPP crystal arthritis associated with longer disease duration (aOR 2.88 [95% CI 2.00-4.14]). Chronic CPP crystal inflammatory arthritis was associated with acute wrist arthritis (aOR 2.92 [95% CI 1.81-4.73]), metacarpophalangeal joint osteoarthritis (aOR 1.87 [95% CI 1.17-2.97]), and scapho-trapezo-trapezoid (STT) joint osteoarthritis (aOR 1.83 [95% CI 1.15-2.91]), and it was negatively associated with either metabolic or familial risk for CPPD (aOR 0.60 [95% CI 0.37-0.96]). CDS was associated with male sex (aOR 2.35 [95% CI 1.21-4.59]), STT joint osteoarthritis (aOR 2.71 [95% CI 1.22-6.05]), and more joints affected with chondrocalcinosis (aOR 1.46 [95% CI 1.15-1.85]).

CONCLUSION

CPPD disease encompasses acute and chronic inflammatory phenotypes, each with specific clinical and imaging features that need to be considered in the diagnostic workup.

Calcium pyrophosphate deposition disease

Calcium pyrophosphate deposition (CPPD) disease is a consequence of the immune response to the pathological presence of calcium pyrophosphate (CPP) crystals inside joints, which causes acute or chronic inflammatory arthritis. CPPD is strongly associated with cartilage degradation and osteoarthritis, although the direction of causality is unclear. This clinical presentation is called CPPD with osteoarthritis. Although direct evidence is scarce, CPPD disease might be the most common cause of inflammatory arthritis in older people (aged >60 years). CPPD is caused by elevated extracellular-pyrophosphate concentrations in the cartilage and causes inflammation by activation of the NLRP3 inflammasome. Common risk factors for CPPD disease include ageing and previous joint injury. It is uncommonly associated with metabolic conditions (eg, hyperparathyroidism, haemochromatosis, hypomagnesaemia, and hypophosphatasia) and genetic variants (eg, in the ANKH and osteoprotegerin genes). Apart from the detection of CPP crystals in synovial fluid, imaging evidence of CPPD in joints by mainly conventional radiography, and increasingly ultrasonography, has a central role in the diagnosis of CPPD disease. CT is useful in showing calcification in axial joints such as in patients with crowned dens syndrome. To date, no treatment is effective in dissolving CPP crystals, which explains why control of inflammation is currently the main focus of therapeutic strategies. Prednisone might provide the best benefit-risk ratio for the treatment of acute CPP-crystal arthritis, but low-dose colchicine is also effective with a risk of mild diarrhoea. Limited evidence suggests that colchicine, low-dose weekly methotrexate, and hydroxychloroquine might be effective in the prophylaxis of recurrent flares and in the management of persistent CPP-crystal inflammatory arthritis. Additionally, biologics inhibiting IL-1 and IL-6 might have a role in the management of refractory disease.

Calcium Pyrophosphate Crystal Formation and Deposition: Where Do we Stand and What Does the Future hold?

PURPOSE OF THE REVIEW

Although calcium pyrophosphate deposition (CPPD) has been known since the 1960s, our understanding of its pathogenesis remains rudimentary. This review aims to illustrate the known mechanisms underlying calcium pyrophosphate (CPP) crystal formation and deposition and explore future directions in research. By examining various perspectives, from basic research to clinical and imaging assessments, as well as new emerging methodologies, we can establish a starting point for a deeper understanding of CPPD pathogenesis.

RECENT FINDINGS

Recent years have seen significant advances in CPPD research, particularly in the clinical field with the development of the 2023 ACR/EULAR classification criteria for CPPD disease, and in imaging with the introduction of the OMERACT ultrasonographic definitions and scoring system. However, progress in basic research has been slower. New laboratory approaches, such as Raman spectroscopy and omics sciences, offer promising insights that may help piece together the puzzle of CPPD. CPPD is a common yet understudied condition. As the population ages and CPPD becomes more prevalent, there is an urgent need to better understand the disease and the mechanisms involved in crystal formation and deposition, in order to improve diagnosis and therapeutic approaches.

Gitelman syndrome with primary hyperparathyroidism: A case report

BACKGROUND

Gitelman syndrome (GS) is a rare autosomal recessive inherited salt-losing tubulopathy, typically devoid of hypercalcemia. Herein, we described one patient of GS presenting with hypercalcemia concomitant with primary hyperparathyroidism (PHPT).

METHODS

On September 28, 2020, a middle-aged female patient was admitted to our hospital with a 12-year history of hypokalemia and hypomagnesemia. Laboratory examinations unveiled hypokalemia with renal potassium wasting, hypomagnesemia, metabolic alkalosis, hypocalciuria, and gene sequencing revealed a homozygous mutation in SLC12A3 (c.179C > T [p.T60M]). Subsequently, the diagnosis of GS was confirmed. In addition, the patient exhibited hypercalcemia and elevated levels of parathyroid hormone. Parathyroid ultrasound revealed left parathyroid hyperplasia, consistent with PHPT. Following aggressive treatment with potassium chloride and magnesium oxide, her serum potassium rose to 3.23 mmol/L, serum magnesium was 0.29 mmol/L, and her joint pain was relieved.

RESULTS

Based on the patient's medical history, laboratory findings, and gene sequencing results, the definitive diagnosis was GS concomitant with PHPT.

CONCLUSION

PHPT should be taken into consideration when patients diagnosed with GS exhibit hypercalcemia. While the serum potassium level readily exceeded the target threshold, correcting hypomagnesemia proved challenging, primarily because PHPT augments urinary magnesium excretion.

Navigating the multifaceted intricacies of the Na+-Cl- cotransporter, a highly regulated key effector in the control of hydromineral homeostasis

The Na+-Cl- cotransporter (NCC; SLC12A3) is a highly regulated integral membrane protein that is known to exist as three splice variants in primates. Its primary role in the kidney is to mediate the cosymport of Na+ and Cl- across the apical membrane of the distal convoluted tubule. Through this role and the involvement of other ion transport systems, NCC allows the systemic circulation to reclaim a fraction of the ultrafiltered Na+, K+, Cl-, and Mg+ loads in exchange for Ca2+ and [Formula: see text]. The physiological relevance of the Na+-Cl- cotransport mechanism in humans is illustrated by several abnormalities that result from NCC inactivation through the administration of thiazides or in the setting of hereditary disorders. The purpose of the present review is to discuss the molecular mechanisms and overall roles of Na+-Cl- cotransport as the main topics of interest. On reading the narrative proposed, one will realize that the knowledge gained in regard to these themes will continue to progress unrelentingly no matter how refined it has now become.

Joint manifestations revealing inborn metabolic diseases in adults: a narrative review

Inborn metabolic diseases (IMD) are rare conditions that can be diagnosed during adulthood. Patients with IMD may have joint symptoms and the challenge is to establish an early diagnosis in order to institute appropriate treatment and prevent irreversible damage. This review describes the joint manifestations of IMD that may be encountered in adults. The clinical settings considered were arthralgia and joint stiffness as well as arthritis. Unspecific arthralgias are often the first symptoms of hereditary hemochromatosis, chronic low back pain may reveal an intervertebral disc calcification in relation with alkaptonuria, and progressive joint stiffness may correspond to a mucopolysaccharidosis or mucolipidosis. Gaucher disease is initially revealed by painful acute attacks mimicking joint pain described as "bone crises". Some IMD may induce microcrystalline arthropathy. Beyond classical gout, there are also gouts in connection with purine metabolism disorders known as "enzymopathic gouts". Pyrophosphate arthropathy can also be part of the clinical spectrum of Gitelman syndrome or hypophosphatasia. Oxalate crystals arthritis can reveal a primary hyperoxaluria. Destructive arthritis may be indicative of Wilson's disease. Non-destructive arthritis may be seen in mevalonate kinase deficiency and familial hypercholesterolemia.

Diagnosis and Treatment of Calcium Pyrophosphate Deposition (CPPD) Disease: A Review

Calcium Pyrophosphate Dihydrate (CPPD) crystal-related arthropathies are a common cause of acute and chronic arthritis caused by the deposition of calcium pyrophosphate crystals in joints and soft tissues, resulting in inflammation and joint damage. They present with a wide spectrum of clinical manifestations and often present challenges to diagnosis and management as they commonly affect older co-morbid patients. The challenges are compounded by a lack of a well-defined description of CPPD. However, an international expert-driven process is underway to develop CPPD classification criteria. Treatment is also problematic as unlike gout, there are no agents available that decrease the crystal burden. Treatment options have often been extrapolated from gout treatment pathways without having extensive trials or a solid evidence base. It is hoped the new CPPD classification guidelines will contribute to large multicentre studies, with well-defined patient cohorts, which will facilitate the production of high-quality evidence to guide the management of this condition. Here, we discuss the barriers and facilitators in diagnosing and treating CPPD-related arthropathy.

Cartilage calcification in osteoarthritis: mechanisms and clinical relevance

Pathological calcification of cartilage is a hallmark of osteoarthritis (OA). Calcification can be observed both at the cartilage surface and in its deeper layers. The formation of calcium-containing crystals, typically basic calcium phosphate (BCP) and calcium pyrophosphate dihydrate (CPP) crystals, is an active, highly regulated and complex biological process that is initiated by chondrocytes and modified by genetic factors, dysregulated mitophagy or apoptosis, inflammation and the activation of specific cellular-signalling pathways. The links between OA and BCP deposition are stronger than those observed between OA and CPP deposition. Here, we review the molecular processes involved in cartilage calcification in OA and summarize the effects of calcium crystals on chondrocytes, synovial fibroblasts, macrophages and bone cells. Finally, we highlight therapeutic pathways leading to decreased joint calcification and potential new drugs that could treat not only OA but also other diseases associated with pathological calcification.

Tophaceous gout in a young man with Gitelman syndrome: a case report with an overview

Gitelman syndrome represents the clinical manifestations of inactivation of the Slc12a3 genes encoding the thiazide-sensitive sodium chloride cotransporter and the Trpm6-Mg genes encoding the magnesium transporters in the distal convoluted tubule. In fact, the biochemical findings resemble those with thiazide diuretics such as hypokalemia, hypomagnesaemia, hypocalciuria, metabolic alkalosis, and low normal blood pressure. He is usually associated with calcium pyrophosphate deposition. Serum uricemia level is rarely affected in Gitelman syndrome. We aimed to report a rare association of chronic gout with Gitelman syndrome, hence the interest of our case. We describe a 29-year-old male patient with a history of Gitelman syndrome associated with articular gout including pelvic localization. We provided pictorial evidence of extensive and diffuse monosodium urate deposition in articular and periarticular structures to confirm the gout origin. A literature review illustrates 4 reported cases of Gitelman syndrome associated with gout. The gender distribution was equal with a mean age of 40 years.