Pachydermoperiostosis: an update

Pseudoacromegaly-A challenging entity in the endocrine clinic: A systematic review

OBJECTIVE

Pseudoacromegaly encompasses conditions with features of acromegaly/gigantism, but no growth hormone (GH) or insulin-like growth factor-1 (IGF-1) excess. We aimed to review published pseudoacromegaly cases evaluated due to clinical suspicion of acromegaly.

DESIGN/PATIENTS

PubMed/Medline search was conducted to identify reported pseudoacromegaly cases, which were systematically reviewed to ensure they met eligibility criteria: (1) presentation suggestive of acromegaly; (2) acromegaly excluded based on normal GH, IGF-1 and/or GH suppression on oral glucose tolerance test (OGTT-GH); (3) diagnosis of the pseudoacromegaly condition was established. Data were retrieved from each case and analysed collectively.

RESULTS

Of 76 cases, 47 were males, mean ages at presentation and at first acromegaloid symptoms were 28 ± 16 and 17 ± 10 years, respectively. Most common conditions were pachydermoperiostosis (47%) and insulin-mediated pseudoacromegaly (IMP) (24%). Acromegaloid facies (75%) and acral enlargement (80%) were the most common features. Measurement of random GH was reported in 65%, IGF-1 in 79%, OGTT-GH in 51%. GH excess was more frequently excluded based on two tests (53%). Magnetic resonance imaging (MRI) was performed in 30 patients, with pituitary adenoma or hyperplasia being reported in eight and three patients, respectively. Investigations differed between cases managed by endocrine and non-endocrine specialists, the former requesting more often IGF-1, OGTT-GH and pituitary MRI.

CONCLUSIONS

Pseudoacromegaly is a challenging entity that may be encountered by endocrinologists. Pachydermoperiostosis and IMP are the conditions most often mimicking acromegaly. Adequate assessment of GH/IGF-1 is crucial to exclude acromegaly, which may be better performed by endocrinologists. Pituitary incidentalomas are common and require careful judgement to prevent unnecessary pituitary surgery.

Role of bisphosphonates in hypertrophic osteoarthropathy: a systematic review

BACKGROUND

The role of bisphosphonates (BP) in hypertrophic osteoarthropathy (HPOA) is unclear. We presented a case of primary HPOA and performed a systematic review of literature on the effect of BP on treatment response in primary and secondary HPOA.

METHODS

The study was prospectively registered in PROSPERO (CRD42022343786). We performed a PubMed literature search that restricted to the English language. We included patients diagnosed with primary or secondary HPOA who received BP. The primary endpoint assessed was the effectiveness of BP on response to pain or arthritis. Secondary outcomes included timing, degree, and duration of response, comparison to other HPOA therapies, impact of BP on radiology, bone scan, bone turnover markers, and adverse effects of BP.

RESULTS

Literature search retrieved only case reports. Forty-five patients (21 primary, 24 secondary HPOA) had received BP. Majority(88.3%) experienced improvement in pain or arthritis. Response was gradual for primary HPOA and within a median of 3 to 7 days for secondary HPOA after treatment with BP. Most patients had reduced bone scan uptake after BP. When other HPOA therapies were tried, half responded to BP after not having previously responded to other therapies, while a third received the treatments concurrently, making it difficult to attribute treatment response to a drug. Reporting of other secondary outcomes was very heterogenous and qualitative to draw conclusions. No major adverse effects have been reported for BP in HPOA.

CONCLUSION

Bisphosphonates provide an effective and safe treatment option for primary and secondary HPOA. However, there is a lack of randomized controlled trials.

Genotype and phenotype characterization of primary hypertrophic osteoarthropathy type 2 and chronic enteropathy associated with SLCO2A1: Report of two cases and literature review

Autosomal recessive type 2 primary hypertrophic osteoarthropathy (PHOAR2) and chronic enteropathy associated with SLCO2A1 (CEAS) are two entities caused by pathogenic variants (PVs) in the SLCO2A1 gene that can coexist or occur independently from one another. We report two cases of PHOAR2 in Mexico with concomitant CEAS and conducted a review of the literature of the reported cases of PHOAR2 and/or CEAS to analyze the relationship between their genotype and phenotype presentation. The patients from our Institution with classical PHOAR2 phenotype and CEAS, harbored SLCO2A1 c.547G > A and c.1768del variants. We reviewed 232 cases, of which 86.6% were of Asian origin, and identified 109 different variants in SLCO2A1. Intron 7, exon 13, and exon 4 were predominantly affected. The two most common PVs were c.940 + 1G > A and c.1807C > T. We found a statistically significant association between SLCO2A1 variants located in intron 7, exons 12, and 13 and the development of CEAS. Missense variants were more frequent in isolated PHOAR2, while a greater proportion of protein-truncating variants (PTVs) were found in CEAS. Further investigation is imperative to elucidate the underlying pathophysiological mechanisms associated with CEAS, thereby facilitating the identification of effective therapeutic interventions.

Reclassification of the HPGD p.Ala13Glu variant causing primary hypertrophic osteoarthropathy

Here, we highlight the case of a 31-yr-old man who had clinical features of primary hypertrophic osteoarthropathy (PHOAR) and harbored a homozygous variant (c.38C > A, p.Ala13Glu) in the HPGD gene, as indicated by whole-exome sequencing (WES). This variant has been previously classified by our laboratory as a variant of uncertain significance (VUS). However, another patient with the same phenotype and the same homozygous variant in HPGD was subsequently reported. In reassessing the variant, the absence of this variant in the gnomAD population database, supporting computational predictions, observation in homozygosity in two probands, and specificity of the phenotype for HPGD, all provide sufficient evidence to reclassify the HPGD c.38C > A, p.Ala13Glu variant as likely pathogenic.

Pachydermoperiostosis: a case report of initial improvement with etoricoxib

Introduction and importance

Pachydermoperiostosis (PDP) is a syndrome characterised by the triad of pachydermia, digital clubbing and periostosis of long bones and its scarce incidence and similarity in clinical features with acromegaly makes the diagnosis challenging. The elevated PGE2 levels have been hypothesised as one of its mechanisms and therapies have been targeted to inhibit this prostaglandin.

Case presentation

A 25-year-old man with no comorbidities presented to OPD with a 10-year history of bilateral pain and swelling of the hands and feets associated with hyperhidrosis, grade IV clubbing and marked skin thickening on his forehead. X-rays revealed hyperostosis of the metacarpals, proximal and middle phalanges and periosteal bone formation with cortical thickening of the ankle joint. Tests done to rule out differentials such as thyroid acropachy, acromegaly, psoriatic arthritis were normal and a clinical diagnosis of PDP, a rare genetic disease characterised by pachyderma, digital clubbing and periostosis was made.

Clinical discussion

The patient was managed conservatively with etoricoxib for 6 months on a follow-up basis. The symptoms were improving and a repeat X-ray showed partial improvement of soft tissue thickening and periostosis.

Conclusion

PDP is a rare diagnosis with no clear consensus on a management approach. Its management with selective COX-2 inhibitors such as etoricoxib should be considered but its long-term effects should be studied further.

Primary hypertrophic osteoarthropathy: genetics, clinical features and management

Primary hypertrophic osteoarthropathy (PHO) is a genetic disorder mainly characterized by clubbing fingers, pachydermia and periostosis. Mutations in the HPGD or SLCO2A1 gene lead to impaired prostaglandin E2 (PGE2) degradation, thus elevating PGE2 levels. The identification of the causative genes has provided a better understanding of the underlying mechanisms. PHO can be divided into three subtypes according to its pathogenic gene and inheritance patterns. The onset age, sex ratio and clinical features differ among subtypes. The synthesis and signaling pathways of PGE2 are outlined in this review. Cyclooxygenase-2 (COX-2) is the key enzyme that acts as the rate-limiting step for prostaglandin production, thus COX-2 inhibitors have been used to treat this disease. Although this treatment showed effective results, it has side effects that restrain its use. Here, we reviewed the genetics, clinical features, differential diagnosis and current treatment options of PHO according to our many years of clinical research on the disease. We also discussed probable treatment that may be an option in the future.

Complete form of pachydermoperiostosis with good initial response to etoricoxib: A case report

Key Clinical Message

Pachydermoperiostosis is a rare genetic disorder that closely resembles acromegaly. Diagnosis is usually based on distinct clinical and radiological features. Oral etoricoxib therapy showed a good initial response in our patient.

Abstract

Pachydermoperiostosis (PDP) is a rare genetic disorder with unclear etiopathogenesis. We report a case of a 38-year-old male who presented with classic features of PDP. Our patient showed a good initial response to etoricoxib therapy but the safety and efficacy over long-term use are yet to be determined in further studies.

Primary pachydermoperiostosis associated with pigmented villonodular synovitis: An unknown association?

Primary pachydermoperiostosis is a rare genetic disease affecting the skin and musculoskeletal system. In contrast to secondary hypertrophic osteoarthropathy, primary pachydermoperiostosis is considered a benign condition. While a variety of associated abnormalities have been described in this form, any association with tumors was previously reported in the literature. We hereby describe the first case of a 20-year-old man with primary pachydermoperiostosis revealed by a knee synovial tumor.

Novel pathogenic variants in SLCO2A1 causing autosomal dominant primary hypertrophic osteoarthropathy

Primary hypertrophic osteoarthropathy (PHO), or pachydermoperiostosis, is characterized by a clinical association including digital clubbing, periostosis and pachydermia. SLCO2A1 and HPGD genes are both responsible for PHO. The pathology is classically defined as an autosomal recessive disorder with clinical variability ranging from a mild to more severe phenotype. However, the hypothesis for an autosomal dominant form suggested for a long time was only demonstrated for the first time in 2021 for SLCO2A1. We aimed to detect a second pathogenic variant by a deep sequencing of the entire SLCO2A1 and HPGD genes, associated with functional transcription analysis in PHO patients harboring only one heterozygous variant. Among 10 PHO patients, 4 presented a single pathogenic or probably pathogenic novel variant in SLCO2A1 in heterozygous status (NM_005630.3: c.234+1G > A, c.1523_1524delCT, c.1625G > A and c.31delC), and the others carried homozygous pathogenic variants. For heterozygous forms, we found no additional pathogenic variant in HPGD or SLCO2A1. PHO can be a dominant form with age at disease onset later than that for the recessive form. This dominant form is not exceptional in young adults. In conclusion, both modes of inheritance of PHO explain the clinical variability and the difference in age at disease onset. Molecular analysis is especially required in the incomplete form to distinguish it from secondary hypertrophic osteoarthropathy.

Case report: Novel homozygous HPGD variant leads to primary hypertrophic osteoarthropathy with intussusception and acro-osteolysis in a Chinese family

Objective

To perform molecular genetic analysis of a patient diagnosed with primary hypertrophic osteoarthropathy (PHO) with malnourishment, intussusception, and acro-osteolysis.

Case presentation

At the age of 7 years, a boy born to a consanguineous couple was diagnosed with PHO attributed to delayed closure of the cranial suture, eczema, clubbing of fingers, and swelling of the knee and ankle. Clinical characteristics and follow-up data for 3 years were collected and analyzed. Trio whole-exome sequencing (WES) and copy number variant sequencing were used to screen for causative genetic variants. Candidate variants of the patient and his parents were confirmed by Sanger sequencing. When he was 7 years old, trio WES found that he had biallelic novel variants c.498 + 1G > A, inherited from his parents, in the HPGD gene. The patient was markedly malnourished. Ultrasonography and computed tomography showed intussusception with a gradual expansion of the duodenum, localized intestinal wall thickening, and acro-osteolysis. Cross-sectional blood tests showed that the patient had continuously decreased levels of serum 25-hydroxy vitamin D and serum ferritin at the age of 7and 10 years.

Conclusion

PHO due to HPGD defects is rare in pediatric patients, and finding homozygous novel c.498 + 1G > A has expanded the spectrum of causative variants of HPGD and provided a clue for genotype-phenotype correlation analysis. Similar to mouse model results, human HPGD deficiency may also cause abnormal digestive tract development, and related secondary vitamin D deficiency and acro-osteolysis should be considered in HPGD-related PHO.

Coincidence of pachydermoperiostosis and synovitis, acne, pustulosis, hyperostosis, osteitis syndrome, a causal or casual association?

Pachydermoperiostosis (PDP) is a rare disorder characterized by skin thickening, acropachia, and periostosis. Synovitis, acne, pustulosis, hyperostosis, osteitis (SAPHO) syndrome is also an orphan disease featured by different dermatological and osteoarthritic manifestations. Herein, we report the first case of an adolescent male diagnosed with both PDP and SAPHO syndrome, presenting with digital clubbing, polyarthralgia, ostealgia, pachydermia and acne on his face, chest and back. Furthermore, we distinguish the characteristics of both diseases and explore the potential pathological mechanism for this coexistence in one patient. Further investigations are needed to establish the detailed pathophysiological association of these 2 diseases.

Approach to the Patient With Pseudoacromegaly

Pseudoacromegaly encompasses a heterogeneous group of conditions in which patients have clinical features of acromegaly or gigantism, but no excess of GH or IGF-1. Acromegaloid physical features or accelerated growth in a patient may prompt referral to endocrinologists. Because pseudoacromegaly conditions are rare and heterogeneous, often with overlapping clinical features, the underlying diagnosis may be challenging to establish. As many of these have a genetic origin, such as pachydermoperiostosis, Sotos syndrome, Weaver syndrome, or Cantú syndrome, collaboration is key with clinical geneticists in the diagnosis of these patients. Although rare, awareness of these uncommon conditions and their characteristic features will help their timely recognition.

Familial Touraine-Solente-Gole syndrome

Touraine-Solente-Gole syndrome is a rare, autosomal dominant multisystem disorder arising from dysregulated prostaglandin synthesis due to underlying genetic defects. Early symptoms are related to skin and soft tissue involvement (coarse facial features, widening of wrists, etc) and may thus be overlooked unless a careful physical examination is carried out. Secondary causes of pachydermoperiosteitis must always be looked for in such patients. During evaluation, a systemic review of all organ systems should be carried out to identify asymptomatic or subclinical involvement of organ systems and identify means to avoid disease progression. Treatment options are limited to steroids and non-steroidal anti-inflammatory drugs. In the absence of definitive guidelines, clinical decisions are largely case based, with no definite duration of drug therapy or screening of potential malignancies outlined in current literature. Mental health and social rehabilitation of these patients due to their disfiguring deformities are an unmet need.

Monoallelic mutations in SLCO2A1 cause autosomal dominant primary hypertrophic osteoarthropathy

Primary hypertrophic osteoarthropathy (PHO) is a rare disease inherited as a recessive or irregular dominant trait and characterized by digital clubbing, pachydermia, and periostosis. Biallelic mutations in HPGD and SLCO2A1, disturbing prostaglandin E₂ (PGE₂ ) catabolism and leading to increased circulating PGE₂ level, cause PHO autosomal recessive 1 (PHOAR1) and PHO autosomal recessive 2 (PHOAR2), respectively. However, no causative genes have been reported for PHO autosomal dominant (PHOAD). Here, we performed Sanger sequencing and whole-genome sequencing (WGS) on DNA samples from seven Chinese PHOAD families; after excluding other single-nucleotide variants (SNVs), structural variations (SVs), and copy number variations (CNVs) in the genomes, we reported six SLCO2A1 monoallelic mutations (c.1660G>A [p.G554R], c.664G>A [p.G222R], c.1106G>A [p.G369D], c.1065dupA [p.Q356TfsX77], c.1293delT [p.S432AfsX48], and c.1807C>T [p.R603X]) in the probands and affected family members. Then, in five other PHO families with probands carrying SLCO2A1 biallelic mutations, we verified that parents with SLCO2A1 monoallelic mutations also displayed PHO manifestations, which further confirmed the pathogenicity of SLCO2A1 monoallelic mutations and illustrated the allelic nature of PHOAD and PHOAR2. Subsequently, through comparison of seven PHOAD probands and 50 PHOAR2 patients, we found onset age in puberty and skewed penetrance rate were similar in both PHO types, but symptoms and signs of PHOAD were milder, including less severe pachydermia (p = .027) and periostosis (p = .005), and less frequent cutis verticis gyrata (p = .011), acne (p = .005), arthralgia (p = .037), and anemia (p = .023). The median urinary PGE₂ level in PHOAD probands was almost half that in PHOAR2 patients (PHOAD 277.58 ng/mmoL creatinine, PHOAR2 473.19 ng/mmoL creatinine; p = .038). Moreover, through the 3-month trial of oral administration of etoricoxib, an effective response similar to that we reported previously in PHOAR2 patients was observed in PHOAD probands. In conclusion, our findings confirm that SLCO2A1 monoallelic mutations are the cause of PHOAD and broaden phenotypic spectrum of PHO. © 2021 American Society for Bone and Mineral Research (ASBMR).

The combined prevalence of classified rare rheumatic diseases is almost double that of ankylosing spondylitis

BACKGROUND

Rare diseases (RDs) affect less than 5/10,000 people in Europe and fewer than 200,000 individuals in the United States. In rheumatology, RDs are heterogeneous and lack systemic classification. Clinical courses involve a variety of diverse symptoms, and patients may be misdiagnosed and not receive appropriate treatment. The objective of this study was to identify and classify some of the most important RDs in rheumatology. We also attempted to determine their combined prevalence to more precisely define this area of rheumatology and increase awareness of RDs in healthcare systems. We conducted a comprehensive literature search and analyzed each disease for the specified criteria, such as clinical symptoms, treatment regimens, prognoses, and point prevalences. If no epidemiological data were available, we estimated the prevalence as 1/1,000,000. The total point prevalence for all RDs in rheumatology was estimated as the sum of the individually determined prevalences.

RESULTS

A total of 76 syndromes and diseases were identified, including vasculitis/vasculopathy (n = 15), arthritis/arthropathy (n = 11), autoinflammatory syndromes (n = 11), myositis (n = 9), bone disorders (n = 11), connective tissue diseases (n = 8), overgrowth syndromes (n = 3), and others (n = 8). Out of the 76 diseases, 61 (80%) are classified as chronic, with a remitting-relapsing course in 27 cases (35%) upon adequate treatment. Another 34 (45%) diseases were predominantly progressive and difficult to control. Corticosteroids are a therapeutic option in 49 (64%) syndromes. Mortality is variable and could not be determined precisely. Epidemiological studies and prevalence data were available for 33 syndromes and diseases. For an additional eight diseases, only incidence data were accessible. The summed prevalence of all RDs was 28.8/10,000.

CONCLUSIONS

RDs in rheumatology are frequently chronic, progressive, and present variable symptoms. Treatment options are often restricted to corticosteroids, presumably because of the scarcity of randomized controlled trials. The estimated combined prevalence is significant and almost double that of ankylosing spondylitis (18/10,000). Thus, healthcare systems should assign RDs similar importance as any other common disease in rheumatology.

Eicosanoid profiling in patients with complete form of pachydermoperiostosis carrying SLCO2A1 mutations

Pachydermoperiostosis (PDP) is a genetic disease characterized by digital clubbing, periostosis, and pachydermia caused by mutated HPGD or SLCO2A1. Plasma prostaglandin (PG)E₂ levels are increased in these patients. However, other eicosanoids have not been quantitated. We aimed to quantitate plasma eicosanoid levels in four patients carrying SLCO2A1 mutations by high-performance liquid chromatography-tandem mass spectrometry. PGE₂ level was elevated in all patients; PGD₂ and 11β-PGF₂ α levels were also increased in some patients, whereas eicosapentaenoic acid, docosahexaenoic acid, and arachidonic acid levels were decreased in all patients. Our data indicate a dysfunctional eicosanoid homeostasis and varied levels of PG in patients with a complete form of PDP carrying SLCO2A1 mutations. PGE₂ levels seem to mostly affect the symptoms, with other eicosanoids possibly having a minor effect.

Assessment score for the diagnosis of a case with pleuroparenchymal fibroelastosis

Idiopathic pleuropulmonary fibroelastosis is an extremely rare lung disease characterized by the combination of fibrosis of the visceral pleura and the fibroelastotic changes transcending in the subpleural lung parenchyma that predominantly affects the upper lobes with accompanying volume loss. It is mostly idiopathic while infection, autoimmunity, bone marrow or lung transplantation and genetic predisposition may be associated with the development of PPFE. The disease is exceptionally rare as approximately ninety cases have been reported in the literature currently. A 35-year-old female presented with exertional dyspnea, dry cough and weight loss. Physical examination demonstrated platythorax, suprasternal notch deepening and fine rales over the upper lobes. Blood count, serum biochemistry, autoimmunity and serologic markers for collagen vascular diseases were within normal limits. Arterial blood gases demonstrated a low pO2 (48 mm Hg) and a high pCO2 (54 mm Hg) values. Chest x-ray showed bilateral parenchymal fibrotic lesions, left pneumothorax, bronchiectasis in the middle and pleural thickening in the upper lung zones while HRCT revealed bilateral apical pleural thickening, traction bronchiectasis, subpleural reticulations, ground-glass opacities and honeycombing in the upper lobes. Bronchoscopy, BAL cytology, smear and culture did not reveal any pathologic findings. Relevant with the clinical, laboratory, radiologic manifestations and the differential diagnosis with other interstitial lung diseases, PPFE was the final diagnosis. The aim of this case report was to present the clinical manifestations of our case. The second crucial objective was to establish a diagnostic scoring system relevant with the literature and the clinical manifestations of the patient.

Primary hypertrophic osteoarthropathy with severe arthralgia identified by gene mutation of SLCO2A1

Male, 41 years old (yo) had been complaining of severe arthralgia. Past History indicated obstruction of intestinal tract at 12 yo and gastric ulcer at 13 yo. He had been suffered from polyarthralgia especially at PIP and MP joints of both hands from 38 yo. Finally, he complained severe arthralgia at PIP and MP joints with clubbed fingers without swelling. Biochemical finding indicated negative rheumatoid factor and anti-CCP antibody and normal MMP-3 level, but slightly increased CRP and ESR levels. Radiological finding indicated periostosis of　long bone without bone erosion and osteoporosis. His facial appearance was acromegalic with cutaneous manifestation of pachydermia and cutis vertices gyrate without abnormal growth hormone response. Histological findings of skin indicated oedema and hyperplasia of sebaceous glands with infiltration of lymphocytes around small blood vessels compatible with pachydermoperiostosis. In this case mutation of SLCO2A1 gene, which coded prostaglandin transport protein, was identified. The mutation c.940 + 1G > A of SLCO2A1 gene results in deletion of exon 7 and truncation of PG transporter (p.Arg288Glyfs*7). We suggest that severe arthralgia was originated from over production of prostaglandin E2. Further studies will be required.

Sudden onset polyarthritis as a paraneoplastic syndrome from non-small cell lung cancer

A 48-year-old male presented to the emergency room for 2 weeks of joint pain and swelling of his four extremities. His symptoms started suddenly and were quite debilitating. His hands, fingers, knees, and ankles were so swollen and painful that he was unable to get out of bed and had to use crutches to ambulate. He also complained of anorexia, nausea, and lack of energy over the past few months, but denied any other complaints. His only medical history was a traumatic left tibia fracture 1 year ago. The patient had a 30-pack year history of smoking tobacco and used marijuana daily.

The patient recently had an arthrocentesis at an outside hospital which was non-diagnostic and showed no infection. Given his symptoms, a thorough rheumatic workup was ordered. The ESR and CRP were elevated. ANA, rheumatoid factor, HLA B27, HIV, hepatitis panel, TSH, T4, Coombs antibodies, gonorrhea, chlamydia, CCP, alpha 1 antitrypsin, parvovirus, fungal antibodies, and myeloperoxidase antibodies were all within the normal range. X-rays of the hands, knees, and ankles were ordered. The images showed diffuse joint swelling with no fractures, dislocations, or hardware mispositioning. It also showed tissue swelling in the fingers that could not exclude hypertrophic pulmonary osteoarthropathy. A chest x-ray revealed a large 8.5 cm oval mass in the right upper lobe. A follow-up CT revealed a massive right upper lobe lung mass concerning for malignancy versus fungal etiology. A CT guided biopsy of the mass was performed and revealed a poorly differentiated non-small-cell lung cancer, favoring adenocarcinoma. Further CT imaging revealed limited stage disease. During the hospitalization, the patient was provided with NSAIDs for his joint pain, which provided minimal benefit. There was little to no improvement in his joint swelling. Oncology was consulted and further evaluation in the outpatient setting was recommended to determine if he would be a surgical candidate and/or to decide the best chemotherapeutic regimen. This case demonstrates an unusual presentation of non-small-cell lung cancer and highlights the importance of maintaining malignancy on the differential diagnosis for sudden arthritis.

Characterization of Mineral and Bone Metabolism Biomarkers in a Chinese Consanguineous Twin Family with Primary Hypertrophic Osteoarthropathy

PURPOSE

Primary hypertrophic osteoarthropathy (PHO) is a rare, autosomal, recessive genetic disease characterized by digital clubbing, periostosis, and pachydermia. The underlying cause for the pathogenesis of this disease is a defect in prostaglandin E2 (PGE2) degradation, caused by mutations in HPGD or SLCO2A1. In this study, we describe the clinical characteristics, SLCO2A1 mutations, and bone metabolic markers of a PHO pedigree from a Chinese consanguineous twin family.

METHODS

Whole blood and urine samples were collected from all the family members. All the exons and exon-intron boundaries of the HPGD and SLCO2A1 genes were amplified using polymerase chain reaction (PCR) and sequenced. The biomarkers of mineral and bone metabolism, including calcium, phosphorus, parathyroid hormone (PTH), 25-hydroxyvitamin D (25(OH)D), bone Gla-protein (BGP), C-terminal telopeptide of type I collagen (β-CTX), and urinary calcium/creatinine ratio (Uca/Ucr) were detected.

RESULTS

A homozygous (nonsense) mutation in the SLCO2A1 gene (c.1807C >T/p.R603 ^∗ ) was detected in the proband. Five heterozygous carriers were also identified among his relatives, including his twin brother. The serum BGP (225.5 ng/ml), β-CTX (4112 pg/ml), and Uca/Ucr (0.63) levels were significantly elevated, while the 25(OH)D (37.1 nmol/L) level was reduced in the proband. The proband's twin brother displayed increased levels of β-CTX (901 pg/ml) and insufficiency of 25(OH)D (67.29 nmol/L), while the other heterozygous carriers only displayed 25(OH)D insufficiency.

CONCLUSION

The patients with PHO displayed an active state of bone reconstruction. There may be a lack of vitamin D, accompanied by an increase in BGP and β-CTX levels. Heterozygous mutations of SLCO2A1 might lead to mild PHO.

Primary hypertrophic osteoarthropathy related gastrointestinal complication has distinctive clinical and pathological characteristics: two cases report and review of the literature

BACKGROUND

Primary hypertrophic osteoarthropathy (PHO) is a rare disease related to HPGD and SLCO2A1 gene mutation. Gastrointestinal involvement of PHO is even rarer with unknown pathogenesis. Clinical features of GI complication in PHO mimics other auto-immune based bowel entities, such as inflammatory bowel diseases and cryptogenic multifocal ulcerous stenosing enteritis (CMUSE). We aimed to analyze the clinical, genetic, radiological and pathological features of Chinese patients with PHO and determine the difference between PHO patients presenting with and without GI involvement.

METHODS

We reported two PHO cases with gastrointestinal involvement and reviewed all the studies of PHO in Chinese population published from January 1, 2000, to April 30, 2018. Clinical and genetic presentations of PHO in Chinese patients were analyzed. We compared the characteristics of those patients with gastrointestinal involvement against those without.

RESULTS

The two patients were both males with complete-form PHO for more than 10 years. GI related symptoms included diarrhea, chronic gastrointestinal hemorrhage, incomplete intestinal obstruction, anemia, and edema, which were unresponsive to etoricoxib treatment. Radiological examinations revealed segmental intestinal stenosis and thickened intestinal wall. Endoscopic findings included multiple ulcers and mucosal inflammation. Both patients had mutations of SLCO2A1 according to sequence analysis. The surgical pathology revealed chronic inflammation involving the intestinal mucosa and submucosa, similar to histological changes in CMUSE. According to the systemic review of 158 Chinese patients with PHO, 17.2% had gastrointestinal involvement, including peptic ulcer, gastric polyps, hypertrophic gastritis, and segmental intestinal stenosis. Patients with gastrointestinal involvement were more likely to have anemia (40.0% vs. 4.5%, P < 0.001), hypoalbuminemia (16.7% vs. 0.9%, P = 0.003), and myelofibrosis (19.0% vs. 0.9%, P = 0.002) than those without. Most patients with gastrointestinal complication had SLCO2A1 mutation (86.7%, 13 /15).

CONCLUSIONS

Digestive tract involvement is uncommon in patients with PHO and often presents with anemia, and hypoalbuminemia resulted from intestinal inflammation. The intestinal pathologic characteristics are distinct from Crohn's disease but similar to CMUSE. Mutations in SLCO2A1 might be the pathogenic cause of GI involvement of PHO. NSAIDs may not be effective for PHO patients with gastrointestinal complications.

Novel SLCO2A1compound heterozygous mutation causing primary hypertrophic osteoarthropathy with Bartter-like hypokalemia in a Chinese family

PURPOSE

Primary hypertrophic osteoarthropathy (PHO) is an inherited disease characterized by digital clubbing, periostosis and pachydermia with defects in the degradation of prostaglandin E2 (PGE2). Mutations in SLCO2A1 gene-encoding prostaglandin transporter (PGT) resulted in PHO, autosomal recessive 2 (PHOAR2). The spectrum of mutations and variable clinical complications of PHOAR2 has been delineated. In this study, we investigated a Chinese PHO family with a manifestation of Bartter-like hypokalemia.

METHODS

Clinical manifestations were collected and genetic analyses were performed in the PHO family.

RESULTS

The 33-year-old male proband had severe hypokalemia due to potassium loss from the kidney, while his brother had mild hypokalemia. After being treated with etoricoxib, the serum potassium level of the patient increased rapidly to the normal range which corresponded with the reduction in his serum PGE2 and PE2 metabolite (PGEM) levels. A novel SLCO2A1 compound heterozygous mutation of p.I284V and p.C459R was identified in two PHO patients in this family.

CONCLUSIONS

The present findings supported that the Bartter-like hypokalemia is a new complication of PHOAR2 caused by the high level of PGE2. Etoricoxib was demonstrated to be effective for the renal hypokalemia in PHO patients.

Primary Hypertrophic Osteoarthropathy Mimicking Juvenile Idiopathic Arthritis: A Novel SLCO2A1 Mutation and Imaging Findings

Primary hypertrophic osteoarthropathy (PHO), also known as pachydermoperiostosis, is a rare, multisystemic, autosomal recessive condition typically presenting with digital clubbing, osteoarthropathy, and various skin manifestations. Radiographs show distinctive periosteal reaction and thickening along the long bones. PHO is caused by homozygous mutations in the HPGD gene in chromosome 4q34.1 or the SLCO2A1 gene in 3q22.1q22.2. Here, we report on a 20-year-old male with enlarged and swollen joints with arthralgia, palmoplantar hyperhidrosis, and large hands and feet with marked digital clubbing. We also present radiographic, MRI, and ultrasonographic features of the case. These clinical and imaging findings were compatible with the diagnosis of PHO, and a novel homozygous mutation, c.576C>G, p.Ile192Met, was found in SLCO2A1.

Inflammatory variant of pachydermoperiostosis responding to methotrexate: a report of two cases

Pachydermoperiostosis is a rare genetic disorder characterized by skin thickening, digital clubbing and periostitis. The pathogenesis is incompletely understood and there are no proven treatments for its manifestations. Although arthritis has been reported in 20–40% cases, most are non-inflammatory in nature and usually treated symptomatically with steroids or NSAIDs. We report two cases of pachydermoperiostosis with inflammatory variant of arthritis and raised inflammatory markers who were treated with tapering dose of prednisolone for 6 weeks and maintained on long-term low dose methotrexate like rheumatoid arthritis and followed for 2 years. In both cases, methotrexate was well tolerated and helped in maintaining symptomatic improvement and slowed the disease progression with significant steroid and NSAID sparing effect. We concluded that there exists an inflammatory subtype of disease where methotrexate can be beneficial.

Chloride Channels in Astrocytes: Structure, Roles in Brain Homeostasis and Implications in Disease

Astrocytes are the most abundant cell type in the CNS (central nervous system). They exert multiple functions during development and in the adult CNS that are essential for brain homeostasis. Both cation and anion channel activities have been identified in astrocytes and it is believed that they play key roles in astrocyte function. Whereas the proteins and the physiological roles assigned to cation channels are becoming very clear, the study of astrocytic chloride channels is in its early stages. In recent years, we have moved from the identification of chloride channel activities present in astrocyte primary culture to the identification of the proteins involved in these activities, the determination of their 3D structure and attempts to gain insights about their physiological role. Here, we review the recent findings related to the main chloride channels identified in astrocytes: the voltage-dependent ClC-2, the calcium-activated bestrophin, the volume-activated VRAC (volume-regulated anion channel) and the stress-activated Maxi-Cl⁻. We discuss key aspects of channel biophysics and structure with a focus on their role in glial physiology and human disease.

Pseudoacromegaly

Individuals with acromegaloid physical appearance or tall stature may be referred to endocrinologists to exclude growth hormone (GH) excess. While some of these subjects could be healthy individuals with normal variants of growth or physical traits, others will have acromegaly or pituitary gigantism, which are, in general, straightforward diagnoses upon assessment of the GH/IGF-1 axis. However, some patients with physical features resembling acromegaly - usually affecting the face and extremities -, or gigantism - accelerated growth/tall stature - will have no abnormalities in the GH axis. This scenario is termed pseudoacromegaly, and its correct diagnosis can be challenging due to the rarity and variability of these conditions, as well as due to significant overlap in their characteristics. In this review we aim to provide a comprehensive overview of pseudoacromegaly conditions, highlighting their similarities and differences with acromegaly and pituitary gigantism, to aid physicians with the diagnosis of patients with pseudoacromegaly.

Novel SLCO2A1 mutations cause gender differentiated pachydermoperiostosis

Primary hypertrophic osteoarthropathy (PHO) is a rare familial disorder with reduced penetrance for females. The genetic mutations associated with PHO have been identified in HPGD and SLCO2A1 which involved in prostaglandin E2 metabolism. Here we report 5 PHO patients from 4 non-consanguineous families. Two heterozygous mutations in solute carrier organic anion transporter family member 2A1 (SLCO2A1) were identified in two brothers by whole-exome sequencing. Three heterozygous mutations and 1 homozygous mutation were identified in other 3 PHO families by Sanger sequencing. However, there was no mutation in HPGD. These findings confirmed that homozygous or compound heterozygous mutations of SLCO2A1 were the pathogenic cause of PHO. A female individual shared the same mutations in SLCO2A1 with her PHO brother but did not have any typical PHO symptoms. The influence of sex hormones on the pathogenesis of PHO and its implication were discussed.

Touraine-Solente-Gole syndrome

Touraine-Solente-Gole syndrome, also known as Pachydermoperiostosis (PDP) or Primary Hypertrophic Osteoarthropathy, is a rare hereditary disorder, which affects both bones and skin. It is characterized by a combination of dermatologic changes (pachydermia or thickening of the skin) and rheumatologic manifestations (periostosis and finger clubbing). Eyelid ptosis which is caused by thickened eyelids (blepharoptosis) is a less common symptom. We report the case of a patient with a complete form of Touraine-Solente-Gole syndrome with bilateral blepharoptosis as presenting feature.

Pachydermoperiostosis in a patient with chronic hepatitis B virus infection referred as acromegaly: a case report

BACKGROUND

Primary hypertrophic osteoarthropathy also known as pachydermoperiostosis is a rare genetic disorder that has often been confused with acromegaly because of similar clinical features. Vascular endothelial growth factors which have been implicated in the clinical features of pachydermoperiostosis, have also been shown to be present in chronic hepatitis and implicated in the malignant transformation of hepatitis B infection to hepatocellular carcinoma. To the best of our knowledge there is one reported case of pachydermoperiostosis with chronic hepatitis B infection. We do not imply a causal relationship between pachydermoperiostosis and hepatitis B infection because pachydermoperiostosis is a genetic disorder; however, the question is raised whether hypertrophic osteoarthropathy is one of the many extrahepatic manifestations of chronic hepatitis B infection.

CASE PRESENTATION

A 21-year-old African (Ghanaian) man with chronic hepatitis B infection was referred to our Endocrine unit as having acromegaly with changing facial features, enlarging hands and feet, and large knee joint effusions which affected activities of daily living. He was finally diagnosed as having pachydermoperiostosis when acromegaly, rheumatological disorders, as well as cardiopulmonary disorders were ruled out. He improved with arthrocentesis, a tapering regime of steroids, non-steroidal anti-inflammatory drugs, and proton pump inhibitors.

CONCLUSIONS

The possible role of hepatitis B in hypertrophic osteoarthropathy, that is, secondary hypertrophic osteoarthropathy, needs to be explored; however, with digital clubbing in his father our patient is likely to have pachydermoperiostosis.

Identification of mutations in the prostaglandin transporter gene SLCO2A1 and phenotypic comparison between two subtypes of primary hypertrophic osteoarthropathy (PHO): A single-center study

Primary hypertrophic osteoarthropathy (PHO) is an inherited disease characterized by digital clubbing, periostosis, and pachydermia. Based on two causative genes, hydroxyprostaglandin dehydrogenase (HPGD) and solute carrier organic anion transporter family member 2A1 (SLCO2A1), PHO is categorized into two subtypes: hypertrophic osteoarthropathy, primary, autosomal recessive 1 (PHOAR1) and hypertrophic osteoarthropathy, primary, autosomal recessive 2 (PHOAR2). In this study, we summarized the clinical manifestations and analyzed SLCO2A1 gene in 23 PHOAR2 patients in our center. As a result, 18 patients displayed complete phenotypes of PHO with digital clubbing, periostosis, and pachydermia. 29 mutations were found in total, and 22 of them were novel mutations including 13 missense, three nonsense, four deletion, one frame-shift and one splicing site mutations. Compared with nine PHOAR1 patients we previously reported, PHO patients with SLCO2A1 mutations were all male and presented with a later onset age. Peptic ulcers and myelofibrosis occurred only in PHOAR2 patients. The urinary level of prostaglandin E2 metabolite (PGEM) is significantly higher in PHOAR2 patients than that in PHOAR1 group. In conclusion, this study was the largest cohort to date to summarize PHOAR2 patients and to assess the phenotypic difference between two subtypes of PHO. The difference of urinary PGEM concentration between two subtypes is helpful for the differential diagnosis of PHO.

Pachydermoperiostosis in a Patient with Crohn's Disease: Treatment and Literature Review

Pachydermoperiostosis (PDP) is a rare disorder characterized by pachydermia, digital clubbing, periostitis, and an excess of affected males. It is the primary form of hypertrophic osteoarthropathy (HOA) and there are some rare associations of PDP with other disorders. Here we describe a patient with Crohn's disease associated with PDP. A 26-year-old man, who was a known case of Crohn's disease, referred with diffuse swelling in the upper and lower limbs and cutis verticis gyrata since 7 years ago. PDP was suspected and endocrinological and radiological studies were conducted for the evaluation of underlying disease. He was prescribed celecoxib, low-dose prednisolone, and pamidronate to control the swelling, periostitis, azathiopurine, and mesalazine according to gastrointestinal involvement. In conclusion, it is important to identify this condition since a misdiagnosis might subject the patient to unnecessary investigations.

Dealing with Chronic Non-Bacterial Osteomyelitis: a practical approach

BACKGROUND

Chronic Non-Bacterial Osteomyelitis (CNO) is an inflammatory disorder that primarily affects children. Although underestimated, its incidence is rare. For these reasons, no diagnostic and no therapeutic guidelines exist. The manuscript wants to give some suggestions on how to deal with these patients in the every-day clinical practice.

MAIN BODY

CNO is characterized by insidious onset of bone pain with local swelling. Systemic symptoms such as fever, skin involvement and arthritis may be sometimes present. Radiological findings are suggestive for osteomyelitis, in particular if multiple sites are involved. CNO predominantly affects metaphyses of long bones, but clavicle and mandible, even if rare localizations of the disease, are very consistent with CNO diagnosis. CNO pathogenesis is still unknown, but recent findings highlighted the crucial role of cytokines such as IL-1β and IL-10 in disease pathogenesis. Moreover, the presence of non-bacterial osteomyelitis among autoinflammatory syndromes suggests that CNO could be considered an autoinflammatory disease itself. Differential diagnosis includes infections, malignancies, benign bone tumors, metabolic disorders and other autoinflammatory disorders. Radiologic findings, either with Magnetic Resonance or with Computer Scan, may be very suggestive. For this reason in patients in good clinical conditions, with multifocal localization and very consistent radiological findings bone biopsy could be avoided. Non-Steroidal Anti-Inflammatory Drugs are the first-choice treatment. Corticosteroids, methotrexate, bisphosphonates, TNFα-inhibitors and IL-1 blockers have also been used with some benefit; but the choice of the second line treatment depends on bone lesions localizations, presence of systemic features and patients' clinical conditions.

CONCLUSION

CNO may be difficult to identify and no consensus exist on diagnosis and treatment. Multifocal bone lesions with characteristic radiological findings are very suggestive of CNO. No data exist on best treatment option after Non-Steroidal Anti-Inflammatory Drugs failure.