Refractory Rickets

Nutritional rickets, caused by vitamin D and/or calcium deficiency is by far the most common cause of rickets. In resource-limited settings, it is therefore not uncommon to treat rickets with vitamin D and calcium. If rickets fails to heal and/or if there is a family history of rickets, then refractory rickets should be considered as a differential diagnosis. Chronic low serum phosphate is the pathological hallmark of all forms of rickets as its low concentration in extracellular space leads to the failure of apoptosis of hypertrophic chondrocytes leading to defective mineralisation of the growth plate. Parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF23) control serum phosphate concentration by facilitating the excretion of phosphate in the urine through their action on the proximal renal tubules. An increase in PTH, as seen in nutritional rickets and genetic disorders of vitamin D-dependent rickets (VDDRs), leads to chronic low serum phosphate, causing rickets. Genetic conditions leading to an increase in FGF23 concentration cause chronic low serum phosphate concentration and rickets. Genetic conditions and syndromes associated with proximal renal tubulopathies can also lead to chronic low serum phosphate concentration by excess phosphate leak in urine, causing rickets. In this review, authors discuss an approach to the differential diagnosis and management of refractory rickets

Primer reporte en Argentina de variante patógena en DMP1 asociada a raquitismo hipofosfatémico autosómico recesivo / First report in Argentina of a pathogenic DMP1 variant associated with autosomal recessive hypophosphatemic rickets

El raquitismo hipofosfatémico hereditario es una condición genética asociada con una mineralización ósea alterada causada por la deficiencia de fosfato. Produce deformidad esquelética y retraso del crecimiento en la infancia. Se describen diferentes patrones de herencia según el locus involucrado. Dado el solapamiento de los fenotipos y la dificultad en analizar genealogías reducidas, los estudios moleculares son importantes para establecer la causa genética y realizar el abordaje familiar. La forma recesiva del raquitismo hipofosfatémico (ARHR, OMIM #241520) es una condición extremadamente poco frecuente reportada en familias de origen europeo y de Oriente Medio. Las mutaciones con pérdida de función del gen DMP1 (dentin matrix acidic phosphoprotein 1) se asocian al raquitismo hipofosfatémico hereditario tipo 1. En este artículo presentamos el primer reporte de una familia argentina con raquitismo hipofosfatémico hereditario por mutación en DMP1

Hereditary hypophosphatemic rickets is a genetic condition associated with impaired bone mineralization caused by phosphate deficiency. It results in skeletal deformity and growth retardation in early childhood. Different inheritance patterns have been described according to the locus involved. Given the phenotypic overlapping and the difficulty in analyzing reduced genealogies, molecular studies are important to establish the genetic cause and implement a family-centered approach. The autosomal recessive form of hypophosphatemic rickets (ARHR, OMIM 241520) is an extremely rare condition reported in families of European and Middle Eastern descent. Loss-of-function mutations in the DMP1 (dentin matrix acidic phosphoprotein 1) gene are associated with hereditary hypophosphatemic rickets type 1. In this article, we describe the first report of an Argentine family with hereditary hypophosphatemic rickets due to a mutation in the DMP1 gene.

Value of serum fibroblast growth factor 23 in diagnosis of hypophosphatemic rickets in children / 中国当代儿科杂志

OBJECTIVES@#To study the value of serum fibroblast growth factor 23 (FGF23) in the diagnosis of hypophosphatemic rickets in children.@*METHODS@#A total of 28 children who were diagnosed with hypophosphatemic rickets in Children's Hospital of Nanjing Medical University from January 2016 to June 2021 were included as the rickets group. Forty healthy children, matched for sex and age, who attended the Department of Child Healthcare of the hospital were included as the healthy control group. The serum level of FGF23 was compared between the two groups, and the correlations of the serum FGF23 level with clinical characteristics and laboratory test results were analyzed. The value of serum FGF23 in the diagnosis of hypophosphatemic rickets was assessed.@*RESULTS@#The rickets group had a significantly higher serum level of FGF23 than the healthy control group (P<0.05). In the rickets group, the serum FGF23 level was positively correlated with the serum alkaline phosphatase level (rs=0.38, P<0.05) and was negatively correlated with maximum renal tubular phosphorus uptake/glomerular filtration rate (rs=-0.64, P<0.05), while it was not correlated with age, height Z-score, sex, and parathyroid hormone (P>0.05). Serum FGF23 had a sensitivity of 0.821, a specificity of 0.925, an optimal cut-off value of 55.77 pg/mL, and an area under the curve of 0.874 in the diagnosis of hypophosphatemic rickets (P<0.05).@*CONCLUSIONS@#Serum FGF23 is of valuable in the diagnosis of hypophosphatemic rickets in children, which providing a theoretical basis for early diagnosis of this disease in clinical practice.

Dental and Endodontic Management in a Patient with Familial X-Linked Hypophosphatemic Rickets

ABSTRACT: The term rickets refers to insufficient or retarded mineralization of the osteoide matrix. X-linked hypophosphatemic (XLH) rickets is a rare genetic disorder characterized by biochemical changes in bone mineralization due to inactivation of the phosphate regulating gene and primary defect of the osteoblasts. The aim of this article was to report a clinical case of XLH, its oral manifestations, periapical changes and dental management. A 31-year old woman female patient was referred to the school of dentistry with pain and sensitivity in the teeth. She had a childhood history of rickets, hypophosphatemia and alteration in Vitamin D. In the oral exam, enamel hypoplasia, microdontia, fistula, caries and periapical lesions and periodontal disease were diagnosed. The radiographic and tomographic exams exhibited the presence of periapical lesions involving various teeth with radiolucent images, suggestive of granuloma or periapical cysts. The treatme nt prioritized the urgency of eliminating pain and removing the foci of infection. Endodontic treatment began in the teeth that had fistula or periapical lesions and in parallel, oral hygiene guidance was provided and periodontal treatment was performed. There was an improvement in the clinical condition with reduction in inflammation and mobility of the teeth. Dentists and health professionals must evaluate the patient as a whole, considering the relations between systemic and oral health. Knowledge of systemic diseases associated with rickets and their characteristics is essential for making a correct oral diagnosis and planning the dental treatment.

RESUMEN: El término raquitismo se refiere a la mineralización insuficiente o retardada de la matriz osteoide. El raquitismo hipofosfatémico ligado al cromosoma X (XLH) es un trastorno genético caracterizado por cambios bioquímicos en la mineralización ósea debido a la inactivación del gen regulador del fosfato y al defecto primario de los osteoblastos. El objetivo de este artículo fue reportar un caso clínico de XLH, sus manifestaciones orales, cambios periapicales y manejo dental. La paciente, una mujer de 31 años, acudió a la Clínica de Semiología de la UFPR con dolor y sensibilidad en varios dientes. Tenía antecedentes infantiles de raquitismo, hipofosfatemia y alteración de la vitamina D. En el examen oral se diagnosticó hipoplasia del esmalte, microdoontia, fístula, caries y lesiones periapicales y enfermedad periodontal. Los exámenes radiográficos y tomográficos mostraron la presencia de lesiones periapicales en varios dientes con imágenes radiolúcidas, sugestivas de granuloma o quistes periapicales. El tratamiento priorizó la urgencia de eliminar el dolor y remover los focos de infección. Se inició tratamiento de endodoncia en los dientes que presentaban fístula o lesiones periapicales y paralelamente se brindó orientación de higiene oral y se realizó tratamiento periodontal. Hubo una mejoría en la condición clínica con reducción de la inflamación y movilidad de los dientes. Los odontólogos y profesionales de la salud deben evaluar al paciente como un todo, teniendo en cuenta las relaciones entre salud sistémica y oral. El conocimiento de las enfermedades sistémicas asociadas al raquitismo y sus características es fundamental para realizar un correcto diagnóstico oral y planificar el tratamiento odontológico.

Guideline for the diagnosis and management of hypophosphatemic rickets/osteomalacia / 中华内分泌代谢杂志

Hypophosphatemic rickets/osteomalacia is a group of rare chronic metabolic bone diseases, which has detrimental impact on the growth, mobility, and life quality of the patients. Because of its rarity, the public awareness remains low, so does in general physician, which leads to delayed diagnosis and treatment. With a vision to standardize the diagnosis and treatment of hypophosphatemic rickets/osteomalacia, Chinese Society of Endocrinology and Chinese Society of Osteoporosis and Bone Mineral Research convened a national group of experts to compose this guideline based on current evidence, which covered the pathogenesis, diagnosis, treatment and management of hypophosphatemic rickets/osteomalacia. In summary, this work outlines recommendations for clinicians, aiming to improve the management of hypophosphatemic rickets/osteomalacia in China.

X-linked hypophosphatemic rickets: a new mutation / Raquitismo hipofosfatêmico ligado ao X: uma nova mutação

Abstract Phosphopenic rickets may be caused by mutations in the PHEX gene (phosphate regulating endopeptidase homolog X-linked). Presently, more than 500 mutations in the PHEX gene have been found to cause hypophosphatemic rickets. The authors report a clinical case of a 4-year-old girl with unremarkable family history, who presented with failure to thrive and bowing of the legs. Laboratory tests showed hypophosphatemia, elevated alkaline phosphatase, normal calcium, mildly elevated PTH and normal levels of 25(OH)D and 1.25(OH)D. The radiological study showed bone deformities of the radius and femur. Clinical diagnosis of phosphopenic rickets was made and the genetic study detected a heterozygous likely pathogenic variant of the PHEX gene: c.767_768del (p.Thr256Serfs*7). This variant was not previously described in the literature or databases. Knowledge about new mutations can improve patient's outcome. Genetic analysis can help to establish a genotype-phenotype correlation.

Resumo O raquitismo fosfopênico pode ser causado por mutações no gene PHEX (ligado ao X do homólogo da endopeptidase que regula o fosfato). Atualmente, mais de 500 mutações no gene PHEX causam raquitismo hipofosfatêmico. Os autores relatam um caso clínico de uma menina de 4 anos com histórico familiar sem relevância, que apresentou falha no crescimento e arqueamento das pernas. Os exames laboratoriais mostraram hipofosfatemia, fosfatase alcalina elevada, cálcio normal, PTH levemente elevado e níveis normais de 25(OH)D e 1,25(OH)D. O estudo radiológico mostrou deformidades ósseas no rádio e no fêmur. O diagnóstico clínico do raquitismo fosfopênico foi realizado e o estudo genético detectou uma provável variante patogênica heterozigótica do gene PHEX: c.767_768del (p.Thr256Serfs*7). Esta variante não foi descrita anteriormente na literatura ou nas bases de dados. O conhecimento sobre novas mutações pode melhorar o desfecho de pacientes. A análise genética pode ajudar a estabelecer uma correlação genótipo-fenótipo.

Raquitismo vinculado al uso de fórmulas elementales: Reporte de caso / Rickets associated to the use of elemental formula: A case report

El raquitismo afecta la diferenciación y mineralización del cartílago de crecimiento como consecuencia, en última instancia, de una alteración en los niveles de fósforo y/o calcio. El secundario a la deficiencia de vitamina D es la forma más frecuente (raquitismo carencial). Las manifestaciones clínicas durante los primeros años de vida suelen comprometer en forma más marcada las epífisis de los huesos.Se describe el caso de un lactante de 8 meses con diagnóstico de alergia a la proteína de la leche de vaca que presentó múltiples fracturas patológicas mientras se encontraba bajo tratamiento con fórmulas lácteas a base de aminoácidos. Se efectuó el diagnóstico de raquitismo hipofosfatémico por deficiencia de fósforo y, tras 3 meses de tratamiento con sales de fosfato, calcio, calcitriol, el abandono paulatino de la leche elemental y el descenso gradual de la medicación antiácida, el paciente evolucionó con curación clínico-radiológica del cuadro

The rickets is a disease that affects the differentiation and mineralization of the growth cartilage, as an ultimate consequence of a balance loss in calcium and phosphate levels. Vitamin D deficiency is the most common cause of the rickets (nutritional rickets). Its clinical manifestation during the first years of life involves long bones epiphysis in a more severe way.We report an 8-month-old infant who was diagnosed with cow ́s milk protein allergy and suffered from multiple fractures while receiving elemental formula as part of his treatment. The final etiology was hypophosphatemic rickets secondary to phosphate deficiency, and after 3 months of phosphate, calcium and calcitriol supplementation, in addition to the gradually reduction of the proportion of elemental formula intake and the decline of the antacid doses, clinical and radiological heal was achieved.

Clinical Manifestation in Females with X-linked Metabolic Disorders: Genetic and Pathophysiological Considerations

Abstract Inborn errors of metabolism are predominantly autosomal-recessive disorders, but several follow an X-linked pattern of inheritance. They are called X-linked recessive, if the female carriers are asymptomatic, and are called X-linked dominant disorders, if almost all females are affected. Conditions, in which some females have symptoms while others are asymptomatic lifelong are simply referred to as X-linked. The aim of this review is to point out the variability in clinical manifestation of affected females in some X-linked metabolic disorders and to discuss on the basis of these examples possible mechanisms that may explain the broad phenotypic spectrum, such as the type of the underlying mutation, the issue of autonomous versus non-autonomous gene expression and the degree of skewing of X-inactivation. The use of the terms "X-linked dominant" and "X-linked recessive" will be discussed.

Autosomal recessive hypophosphatemic rickets 1 caused by DMP1 mutation: one pedigree study / 中华内分泌代谢杂志

In the present study, the clinical features of a patient with autosomal recessive hypophosphatemic rickets 1 caused by dentin matrix protein 1(DMP1)gene mutation and her family members were investigated. DMP1 gene from peripheral blood was sequenced by Sanger sequencing, and the known mutation was verified among her family members and 250 healthy populations. The proband was a 42-year-old female with bone deformity of both lower limbs, bone pain, and short stature. The results of X-rays and laboratory examination were consistent with the hypophosphatemic rickets reported before. A homozygous mutation(c.2T> C)in DMP1 was identified by Sanger sequencing in the proband, her son and daughter were heterozygous for c. 2T> C.

Vitamin D-dependent rickets (VDDR) type 1: case series of two siblings with a CYP27B1 mutation and review of the literature / Raquitismo dependente de vitamina D: tipo 1: série de casos de dois irmãos com mutação CYP27B1 e revisão da literatura

Abstract Two siblings presented with clinical and biochemical features of rickets, initially suspected as hypophosphatemic rickets. There was no improvement initially, hence the siblings were reinvestigated and later diagnosed as having vitamin D-dependent rickets (VDDR) type 1 due to a rare mutation in the CYP27B1 gene encoding the 1α-hydroxylase enzyme. Both siblings improved with calcitriol supplementation. The initial presentation of VDDR is often confusing and algorithmic evaluation helps in diagnosis. We also present a brief review of the literature, including genetics.

Resumo Dois irmãos apresentaram características clínicas e bioquímicas do raquitismo, com suspeita clínica inicial de raquitismo hipofosfatêmico. Não houve melhora no início, portanto os irmãos foram reavaliados e, posteriormente, diagnosticados com raquitismo dependente de vitamina D (VDDR) tipo 1 devido a uma rara mutação no gene CYP27B1, que codifica a enzima 1a-hidroxilase. Ambos os irmãos melhoraram com a suplementação de calcitriol. A apresentação inicial do VDDR geralmente é confusa e a avaliação algorítmica ajuda no diagnóstico. Também apresentamos uma breve revisão da literatura, incluindo genética.

Prevalence of oral manifestations of hypophosphatemic rickets in patients treated in a peruvian pediatric hospital / Prevalencia de manifestaciones bucales del raquitismo hipofosfatémico de pacientes atendidos en un hospital pediátrico peruano

Objective: To describe the prevalence of oral manifestations of hypophosphatemic rickets in patients treated in a Peruvian referral pediatric hospital during the years 2012-2016. Material and methods: An observational, descriptive, retrospective, cross-sectional study was carried out. The sample consisted of patients diagnosed with hypophosphatemic rickets who attended the outpatient clinic of the Stomatology Service and the Genetics Service of the National Institute of Child Health (INSN), Lima, Peru, between the years 2012-2016. The research project was assessed and approved by the Research Ethics Committee of the Health Service. Medical records stored in a database of the health institution with the Code CIE E83.3, which corresponds to the diagnosis of Hypophosphatemic Rickets, were requested for the study. Results: Fifteen children received health care, of which only 10 were treated at the Stomatology Service. The distribution of the data was obtained from these 10 patients according to the proposed objective. A higher frequency of gingival lesions was found at the soft tissue level (41.18%); at the bone tissue level, only one case of dentigerous cyst was observed; and at the dental level, 90% of the patients had dental caries. Conclusion: The most frequent oral manifestations of hypophosphatemic rickets in pediatric patients treated at the National Institute of Child Health (2012-2016) were gingivitis and dental caries.

Objetivo:Describir la prevalencia de las manifestaciones bucales del raquitismo hipofosfatémico de pacientes atendidos en un hospital pediátrico de referencia peruano durante los años 2012-2016. Material y Métodos:Se realizó un estudio tipo observacional, descriptivo, retrospectivo, transversal. Para la selección de la muestra se consideró a los pacientes que acudieron a la consulta externa del Servicio de Odontoestomatología y el Servicio de Genética del Instituto Nacional de Salud del Niño, Lima, Perú; en el periodo comprendido entre los años 2012-2016 y que presentaron como diagnóstico Raquitismo Hipofosfatémico. El proyecto de investigación fue evaluado por un Comité de Ética en Investigación del servicio de salud. Se solicitaron las historias clínicas consignadas en una base de datos de la institución de salud con el Código CIE E83.3, que corresponde a este diagnóstico. Resultados: Fueron atendidos 15 niños, de los cuales solo 10 fueron tratados en el Servicio Odontoestomatología; siendo de estos 10 pacientes la distribución de los datos obtenidos según el objetivo propuesto. Se encontró mayor frecuencia de lesiones a nivel de tejido blando de gingivitis con 41.18%, a nivel de tejido óseo solo se presentó un caso de quiste dentígero; y a nivel de tejido dental el 90% de los pacientes presentó caries dental. Conclusión: Las manifestaciones bucales más frecuentes del raquitismo hipofosfatémico de pacientes pediátricos atendidos en el Instituto Nacional de Salud del Niño (2012-2016), fueron la gingivitis y caries dental.

Intramastoid Phosphaturic Mesenchymal Tumor Causing Hypophosphatemic Osteomalacia Detected on ⁶⁸Ga-DOTATATE PET/CT But Not on (99m)Tc-Sestamibi and ¹⁸F-FDG Scans / 대한핵의학회잡지

⁶⁸Ga-DOTATATE uptake in mesenchymal tumors causing hypophosphatemic osteomalacia has been recently described. Herein, we present a case of ⁶⁸Ga-DOTATATE uptake in an intramastoid phosphaturic mesenchymal tumor that had not been depicted in previous (99m)Tc-Sestamibi and ¹⁸F-FDG scans. The lesion was surgically removed and the phosphorus level increased to the normal range.

Uveítis anterior aguda asociada a raquitismo renal hipofosfatémico / Acute anterior uveítis associated to hypophosphatemic renal ricketts

Los raquitismos hipofosfatémicos hereditarios son un grupo de enfermedades caracterizadas por la pérdida renal de fosfatos. Cursan con hipocrecimiento disarmónico y deformidades óseas. La forma más común es el raquitismo hipofosfatémico ligado al cromosoma X, el cual es causado por mutaciones inactivantes en el gen PHEX. El objetivo de nuestro trabajo fue describir las alteraciones oculares encontradas y la evolución clínica en un paciente con raquitismo hipofosfatémico hereditario y uveítis anterior. Se presenta un niño de 9 años de edad con diagnóstico de raquitismo hipofosfatémico hereditario, valorado en el Servicio de Uveítis del Instituto Cubano de Oftalmología Ramón Pando Ferrer por presentar dolor ocular y molestias a la luz en el ojo derecho. En la exploración oftalmológica se constata una uveítis anterior con hipopión en el ojo derecho y depósitos de cristales en todo el espesor corneal y el iris en ambos ojos. Se indicaron esteroides tópicos con resolución del proceso inflamatorio. Los hallazgos en el segmento anterior del paciente son sugestivos de cistinosis, donde el acúmulo de cristales es la alteración corneal más típica de las manifestaciones oculares, con una incidencia del 90 por ciento en niños menores de un año, y los primeros órganos afectados son los riñones. Los raquitismos hipofosfatémicos hereditarios pueden cursar con depósitos de cristales corneales y procesos inflamatorios de la úvea anterior(AU)

Hereditary hypophosphatemic rickets are a group of diseases characterized by renal loss of phosphates. They appear with disharmonic hypogrowth and bone deformities. The most common form is the X-chromosome-linked hypophosphatemic rickets which is caused by inactivating mutations in PHEX gene. The objective of our work was to describe the ocular alterations and the clinical evolution in a patient with hereditary hypophosphatemic rickets and previous uveitis. Here is the case of a 9 years-old boy diagnosed with hereditary hypophosphatemic rickets, who was seen at the Uveitis Service of Ramon Pando Ferrer Cuban Institute of Ophthalmology. He presented with ocular pain and feeling of discomfort to light in his right eye. The ophthalmological exam yielded anterior uveitis with hypopyon in his right eye and crystal depots in the whole corneal thickness and the iris of both eyes. Topical steroids were prescribed to treat the inflammatory process. The findings in the anterior segment of the patients indicated the presence of cystinosis in which the accumulation of crystals is the most typical corneal alteration among the ocular manifestations. Its incidence reaches 90 percent in under one year-old children and the first affected organs are the kidneys. The hereditary hypophosphatemic rickets may appear with corneal crystal depots and inflammatory processes in the anterior uvea(AU)

Raquitismo hipofosfatêmico: relato de caso / Hypophosphatemic rickets: case report

RESUMO Objetivo: O raquitismo hipofosfatêmico precisa ser precocemente diagnosticado porque seu tratamento previne sequelas incapacitantes. Este relato alerta para a doença. Relato de caso: Relato de perfil metabólico, depuração de creatinina, estado nutricional e desenvolvimento pôndero-estatural de paciente com características clínico-laboratoriais de raquitismo hipofosfatêmico, atendido em ambulatório de tubulopatias por período de 12 meses. Chegou ao serviço após tempo prolongado acamado, dependente de ventilação mecânica e com perfil metabólico ósseo alterado. Terapêutica consistiu na administração de fósforo (inicial: 65 mg/kg/dia, final: 24,2 mg/kg/dia), cálcio (inicial: 127 mg/kg/dia, final: 48,4 mg/kg/dia) e calcitriol (inicial: 0,06 mcg/kg/dia, final: 0,03 mcg/kg/dia), e a análise constou da descrição das consultas, utilizando-se mediana de exames laboratoriais e dados antropométricos. Observou-se nítida melhora inicial do padrão respiratório do paciente, que evoluiu com ventilação espontânea e deambulação autônoma; com exames laboratoriais: cálcio (mg/dL) inicial 7,1, final 10,1; fósforo (mg/dL) inicial 1,7, final 3,2; magnésio (mg/dL) inicial 1,5, final 2,1; paratormônio (pg/L) inicial 85,8, final 52,7; fosfatase alcalina (UI/L) inicial 12660, final 938; e melhora do desenvolvimento pôndero-estatural (escore Z: E/I inicial: -6,05, final -3,64; P/I: inicial -2,92, final -1,57) com presença de litíase transitória. A depuração de creatinina (mL/min/1,73 m2sc) foi constante durante o seguimento. O tratamento propiciou benefícios clínicos, bioquímicos e nutricionais, mas, apesar da boa resposta inicial, a família abandonou o seguimento por dois anos, apresentando o paciente piora da deambulação e das deformidades esqueléticas. Comentários: Não apenas diagnóstico precoce é necessário, como também a adesão ao tratamento é fundamental para o sucesso na condução dessa patologia.

ABSTRACT Objective: Early diagnosis and immediate treatment of hypophosphatemic rickets is of utmost importance as it may prevent subsequent sequelae. This report aims at warning pediatricians to consider the presence of the disease. Case description: Description of the metabolic profile, creatinine clearance, nutritional status, weight and body structure of a patient who presented the clinical-laboratorial characteristics of hypophosphatemic rickets and was followed in an outpatient clinic for tubulopathies over the period of 12 months. The patient had been bedridden for some time, was dependent on mechanical ventilation and presented an altered metabolic bone condition. Treatment was phosphate (initial: 65 mg/kg/day and final: 24,2 mg/kg/day), calcium (initial: 127 mg/kg/day, final: 48,4 mg/kg/day) and calcitriol (initial: 0.06 mcg/kg/day, final: 0.03 mcg/kg/day). The patient improved, evolving into spontaneous breathing and walking unaided. Laboratory results: calcium (mg/dL) initial 7.1, final 10.1; phosphate (mg/dL) initial 1.7 final 3.2; magnesium (mg/dL) initial 1.5 final 2.1, parathyroid hormone (pg/l) initial 85.8, final 52.7, alkaline phosphatase (UI/l) initial 12660, final 938; there was also improvement in weight/structural development (Z score: H/A initial: -6.05, final -3.64; W/A: initial -2.92, final -1.57) with presence of transitory gallstones. Creatinine clearance (mL/min/1.73m2bsa) was constant. The medication improved his laboratory results and nutritional status, but the patient did not return for two years for follow-up and, during this period, his condition has noticeably deteriorated. Comments: Early diagnosis and follow-up are essential in dealing with this pathology.

An Uncommon Case of Bilateral Pathologic Hip Fractures: Antiviral Drug-induced Osteomalacia in a Patient with Hepatitis B / 대한고관절학회지

The long-term use of adefovir and tenofovir–antiviral medications commonly used to treat chronic hepatitis B–can be associated with proximal renal tubular dysfunction resulting in significant hypophosphatemic osteomalacia. However, there have been few reports about pathological fractures requiring surgical stabilization in cases of antiviral drug-induced hypophosphatemic osteomalacia. We present the case of a 51-year-old man who sustained bilateral pathological hip fractures associated with antiviral drug-induced hypophosphatemic osteomalacia. To treat a lamivudine-resistant hepatitis-B viral infection, the patient received adefovir for 7 years followed by tenofovir for the subsequent 3 years. He had suffered from polyarthralgia and generalized weakness for 2 years prior to presentation at our clinic. Misdiagnosis and inadequate management of his condition accelerated weakness of the bone matrix and ultimately induced pathological fractures. The patient was managed via cementless total hip arthroplasty on the left hip and internal fixation on the right hip. This case highlights that orthopaedic surgeons should consider the possibility of hypophosphatemic osteomalacia if patients receiving antiviral drugs complain of polyarthralgia and generalized weakness.

Analysis of clinical diagnosis and treatment of 20 children with hypophosphatemic tickets / 中华实用儿科临床杂志

Objective To analyze the clinical diagnosis and treatment data of 20 children with hypophosphatemic rickets (HR) in order to improve the clinical diagnosis and treatment of HR.Methods The retrospective analysis of clinical data of 20 cases with HR who were hospitalized at Children's Hospital of Nanjing Medical University from May,2010 to April,2016 was performed to summarize the clinical characteristics.All patients were analyzed for the phosphate regulating gene with homologies to endopeptidase on the X chromosome(PHEX) gene by direct sequencing.If no mutations were detected,multiplex ligation-dependent probe amplification analysis was performed.Results All of the 20 cases with HR showed different degrees of growth retardation and typical X-ray rickets.After treatment,the clinical features were improved.Height standard deviation score (HSDS) was improved significantly with longer treatment time,and the difference was statistically significant(P =0.027).There was a correlation between the blood phosphorus fluctuation and secondary hyperparathyroidism(P ＜ 0.05).Nineteen cases had PHEX gene mutations.Truncating mutations was the most frequent mutation type,and 4 new mutations were found.Conclusions Clinical characteristics,laboratory test results and X-ray examination are important clinical index for the diagnosis of HR,and PHEX gene test can be used as an important auxiliary diagnostic tool.Early diagnosis and treatment can significantly improve the clinical manifestations of the patients.

A novel de novo mosaic mutation in PHEX in a Korean patient with hypophosphatemic rickets

X-linked hypophosphatemic rickets is caused by loss-of-function mutations in PHEX, which encodes a phosphate-regulating endopeptidase homolog. We report a 26-year-old man with X-linked hypophosphatemic rickets who showed decreased serum phosphate accompanied by bilateral genu valgum and short stature. He had received medical treatment with vitamin D (alfacalcidol) and phosphate from the age of 3 to 20 years. He underwent surgery due to valgus deformity at the age of 14 and 15. Targeted gene panel sequencing for Mendelian genes identified a nonsense mutation in PHEX (c.589C>T; p.Gln197Ter) and a mosaic pattern where only 38% of sequence reads showed the variant allele. This mutation was not found in his mother, who had a normal phenotype. This is a case of a sporadic nonsense mutation in PHEX and up to date, this is the first case of a mosaic mutation in PHEX in Korea.

Síndrome de Fanconi y raquitismo hipofosfatémico asociado al uso de tenofovir en una niña infectada con VIH / Tenofovir-associated Fanconi`s syndrome and rickets in a HIV infected girl

El tenofovir (TDF) es un inhibidor de la transcriptasa reversa análogo de nucleótidos, aunque tiene buena tolerabilidad y alta actividad antirretroviral, su efecto sobre el riñón ha sido un motivo de preocupación. Objetivo: Describir el caso de una niña infectada por VIH que presenta síntomas y hallazgos de laboratorio compatibles con un síndrome de Fanconi durante el tratamiento con TDF como parte de su terapia antirretroviral. Caso clínico: Niña infectada por el VIH-1, que después de 18 meses con el tratamiento con TDF presentó pérdida de fuerza y dolor de las extremidades inferiores con deterioro funcional. Los hallazgos de laboratorio fueron compatibles con el síndrome de Fanconi. Las radiografías mostraron fractura bilateral de cadera y muñecas. El síndrome de Fanconi se recuperó por completo cuatro meses después del cambio de terapia antirretroviral. Conclusiones: Los médicos que prescriben TDF deben estar preparados para detectar signos y síntomas indicativos de disfunción renal y considerar de inmediato el cambio del fármaco a otro antirretroviral.

Tenofovir (TDF) is an inhibitor of reverse transcriptase nucleotide analogue, although it has good tolerability and high anti-retroviral activity, its effect on the kidney has been a concern. Objective: To describe a girl infected with HIV who presented Fanconi syndrome during antiretroviral therapy with TDF. Clinical case: We describe a HIV-1-infected girl, who after 18 months treatment with TDF presented loss of strength and pain of the lower extremities with functional impairment. Laboratory findings were consistent with Fanconi syndrome. Radiographs showed bilateral hip fracture and wrists. Full recovery of Fanconi syndrome was achieved four months after changing antiretroviral therapy. Conclusions: TDF-prescribing physicians must be prepared to detect signs and symptoms of renal dysfunction and immediately consider switching to another antiviral drug.

X-linked Hypophosphatemic Rickets, del(2)(q37.1;q37.3) Deletion Syndrome and Mosaic Turner Syndrome, mos 45,X/46,X, del(2)(q37.1;q37.3) in a 3-year-old Female

There are currently no published cases that report concomitant Turner syndrome (TS), 2q37 deletion syndrome and X-linked hypophosphatemic rickets (XLH). Interestingly, since the clinical phenotypes of TS and 2q37 deletion syndrome overlap, the correct diagnosis may be missed without a standardized approach to genetic testing consisting of both karyotype and microarray. Both chromosome anomalies have been associated with short stature and a variety of skeletal abnormalities however to date no reports have associated these syndromes in association with a phosphate regulating endopeptidase homolog, X-linked (PHEX) gene deletion resulting in XLH. We report a 3-year-old female with 3 concurrent genetic disorders including a 9.98 Mb terminal deletion of chromosome 2: del(2)(q37.1;q37.3), XLH secondary to a small microdeletion of part of the PHEX gene, and mosaic TS (mos 45,X[32]/46,X[18]). This is the first case report of a patient with 2q37 deletion syndrome and mosaic TS (mos 45,X[32]/46,X[18]) found to have XLH secondary to an interstitial constitutional PHEX gene deletion. Her severe phenotype and multiple genotypic findings reinforce the importance of thorough genetic testing in the setting of complicated phenotypic presentations.

Phenotype of Dent Disease in a Cohort of Indian Children.

Objective: To describe the clinical and genotypic features of Dent disease in children diagnosed at our center over a period of 10 years. Design: Case series. Setting: Pediatric Nephrology Clinic at a referral center in Northern India. Methods: The medical records of patients with Dent disease diagnosed and followed up at this hospital from June 2005 to April 2015 were reviewed. The diagnosis of Dent disease was based on presence of all three of the following: (i) low molecular weight proteinuria, (ii) hypercalciuria and (iii) one of the following: nephrolithiasis, hematuria, hypophosphatemia or renal insufficiency, with or without mutation in CLCN5 or OCRL1 genes. Results: The phenotype in 18 patients diagnosed with Dent disease during this period was characterized by early age at onset (median 1.8 y), and polyuria, polydipsia, salt craving, hypophosphatemic rickets and night blindness. Rickets was associated with severe deformities, fractures or loss of ambulation in six patients. Nephrocalcinosis was present in three patients, while none had nephrolithiasis. Generalized aminoaciduria was seen in 13 patients, two had glucosuria alone, and one had features of Fanconi syndrome. Over a median follow up of 2.7 years, one patient developed renal failure. Genetic testing (n=15) revealed 5 missense mutations and 3 nonsense mutations in CLCN5 in 13 patients. Five of these variations (p.Met504Lys, p.Trp58Cys, p.Leu729X, p.Glu527Gln and p.Gly57Arg) have not been reported outside the Indian subcontinent. Conclusion: Our findings suggest a severe phenotype in a cohort of Indian patients with Dent disease.