Introduction: X-linked hypophosphatemia (XLH) is a rare genetic disorder caused by PHEX mutations, characterized by chronic hypophosphatemia and renal phosphate wasting, resulting in skeletal, dental, and extra-skeletal complications. To date, no data from Malaysia are currently available on clinical characteristics or health-related quality of life (HRQoL) in paediatric patients. Methodology: This cross-sectional study evaluated HRQoL among children and adolescents with XLH, using validated PROMIS (PatientReported Outcomes Measurement Information System) instruments, sociodemographic and clinical factors associated with HRQoL. This includes children and adolescents with confirmed XLH followed up at Universiti Malaya Medical Centre (UMMC) between November 2024 and March 2025. Results: Seventeen patients were analyzed (76.5% female and 23.5% male). The mean age at symptom onset was 2.82 ± 2.42 years, with a mean age at diagnosis of 5.21 ± 3.29 years. All patients continued to have musculoskeletal complications, including short stature (76.5%), bowing of legs (76.5%), bone/joint pain (47.1%), muscle pain (47.1%), and dental complications (52.9%). Serum alkaline phosphatase improved significantly (p = 0.011); persistent hypophosphatemia and ongoing musculoskeletal manifestations indicated suboptimal disease control. Elevated parathyroid hormone levels and an increase in urine calciumto-creatinine ratio (p = 0.020) lead to secondary hyperparathyroidism and nephrocalcinosis. Adherence to conventional therapy was poor. Non-adherence was associated with worse pain outcomes (higher pain interference [p = 0.037] and greater pain intensity [p = 0.025]). PROMIS scores revealed severely impaired mobility (mean T-score 31.31 ± 12.17), increased fatigue (mean T-score 54.22 ± 7.60), and high pain interference (mean T-score 63.11 ± 9.50). Larger household size was also strongly associated with higher pain intensity (p = 0.004). Conclusion Malaysian children and adolescents with XLH continue to have significantly poor HRQoL, particularly in mobility, fatigue, and pain. These findings highlight the need for access to targeted therapies, such as burosumab, to improve long-term outcomes and QOL in XLH patients.
Adolescent ; Child ; Familial Hypophosphatemic Rickets ; Malaysia ; Quality of Life

Dent disease is a rare X-linked recessive inherited renal tubular disorder characterized by low molecular weight proteinuria (LMWP), hypercalciuria, nephrocalcinosis, and other clinical features, and can lead to progressive renal failure. It is primarily caused by mutations in the CLCN5 gene. This article reports the case of a 10-year-old male patient of Chinese descent who was incidentally found to have asymptomatic proteinuria during a routine health examination. Comprehensive biochemical testing and clinical evaluation revealed significant LMWP and hypercalciuria, while renal biopsy showed mesangial cell and matrix proliferation. Whole exome sequencing identified a novel deletion mutation in the CLCN5 gene (NM_001127899.4, c.1158delC, p.F387Lfs*42) causing a frameshift and premature termination, which is likely to disrupt its role in chloride/hydrogen ion exchange and endosomal acidification. Bioinformatic analysis indicated the variant is pathogenic. Genetic testing plays an important role in diagnosing rare kidney diseases. Early identification of pathogenic mutations is essential for facilitating timely intervention and appropriate management, potentially enhancing patient outcomes. This report expands the CLCN5 mutation spectrum and contributes to understanding the genetic and molecular mechanisms of Dent disease.
Humans ; Chloride Channels/genetics* ; Dent Disease/genetics* ; Male ; Child ; Computational Biology ; Mutation ; Proteinuria/genetics* ; Hypercalciuria/genetics*

OBJECTIVE: To explore the clinical features and molecular etiology of a patient with Dent disease due to variant of CLCN5 gene. METHODS: A male patient with Dent disease diagnosed at the First Affiliated Hospital of Zhengzhou University in September 2023 was selected as the study subject. Clinical data of the patient were collected. Whole exome sequencing (WES) was carried out for the patient and his family members. Pathogenicity of candidate variant was verified by Sanger sequencing and bioinformatic analysis. This study has been approved by the Medical Ethics Committee of the Hospital (Ethics No. KS-2018-KY-36). RESULTS: The patient, a 15-year-old male, was admitted due to proteinuria and hematuria. Ultrasonography showed diffuse echogenic changes in both kidneys. Renal biopsy revealed structural dysfunction of renal tubules. Electron microscopy revealed minor tubular and glomerular lesions. The patient was found to harbor a hemizygous c.701dupA (p.Y234Ter) variant of the CLCN5 gene, which was derived from his mother. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was rated as pathogenic (PVS1+PM2). Bioinformatic analysis using multiple software predicted the deleterious effect of the variant. CONCLUSION The hemizygous c.701dupA (p.Y234Ter) variant of the CLCN5 gene probably underlay the pathogenesis of Dent disease in this patient. Above finding has enriched the mutational spectrum of the CLCN5 gene.
Adolescent ; Female ; Humans ; Male ; Chloride Channels/genetics* ; Dent Disease/genetics* ; Exome Sequencing ; Mutation ; Pedigree

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 (r_s=0.38, P<0.05) and was negatively correlated with maximum renal tubular phosphorus uptake/glomerular filtration rate (r_s=-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.
Child ; Humans ; Fibroblast Growth Factor-23 ; Fibroblast Growth Factors ; Familial Hypophosphatemic Rickets/diagnosis* ; Rickets, Hypophosphatemic/diagnosis*

An 18-day-old male infant was admitted to the hospital due to recurrent hyperkalemia for more than 10 days. The neonate had milk refusal and dyspnea. The blood gas analysis revealed recurrent hyperkalemia, hyponatremia and metabolic acidosis. Adrenocortical hormone replacement therapy was ineffective. Additional tests showed a significant increase in aldosterone levels. Family whole exome sequencing revealed that the infant had compound heterozygous in the SCNNIA gene, inherited from both parents. The infant was diagnosed with neonatal systemic pseudohypoaldosteronism type I. The infant's electrolyte levels were stabilized through treatment with sodium polystyrene sulfonate and sodium supplement. The infant was discharged upon clinical recovery. This study provides a focused description of differential diagnosis of salt-losing syndrome in infants and introduces the multidisciplinary management of neonatal systemic pseudohypoaldosteronism type I.
Infant ; Infant, Newborn ; Humans ; Male ; Pseudohypoaldosteronism/genetics* ; Hyperkalemia/etiology* ; Hyponatremia/diagnosis* ; Diagnosis, Differential

Introduction: Gitelman Syndrome (GS), a rare autosomal recessive inherited disorder, is frequently unrecognized in the clinical setting. GS typically manifests with severe hypokalemia with debilitating and potentially fatal consequences if untreated. As of writing, confirmatory genetic assays are currently unavailable in the country, and the diagnosis of GS is primarily based on several biochemical laboratory tests. This results in the difficulty with prompt diagnosis of GS in the locality. Case: We present a 52-year-old male who came in with chronic, intermittent paraparesis associated with persistent hypokalemia. A diagnosis of GS was made biochemically based on renal wasting of potassium and magnesium, hypocalciuria, and metabolic alkalosis. Electrolyte correction with lifelong supplementation, and administration of Spironolactone resulted in the resolution of bilateral leg weakness. Electrolyte levels were maintained within normal limits in the outpatient setting. Conclusion GS is an uncommon potentially debilitating disorder that may lead to problematic, potentially fatal consequences to electrolyte abnormalities if left untreated. The lack of awareness and consequent delay in the diagnosis, and the unavailability of confirmatory genetic testing remains a clinical challenge. Timely recognition and initiation of treatment leads to early control of electrolyte levels, and better prognosis.
Gitelman&rsquo ; s Syndrome ; Paraparesis ; Hypokalemia ; Hypomagnesemia ; Spironolactone ; Case Report

OBJECTIVE: To explore the clinical features and genetic etiology of a patient with primary distal renal tubular acidosis (dRTA). METHODS: A child who was diagnosed with primary dRTA at the Xi'an Children's Hospital in April 2021 due to poor appetite and persistent crying was selected as the study subject. Clinical data of the patient was collected. Whole exome sequencing (WES) was carried out for the child. Candidate variants were validated by Sanger sequencing of his family members. RESULTS: The child, a 1-month-and-18-day male, had featured poor appetite, persistent crying, poor weight gain and dehydration. Laboratory examination has suggested metabolic acidosis, hyperchloremia, hypokalemia, abnormal alkaline urine and anemia. Ultrasonographic examination of the urinary system revealed calcium deposition in renal medulla. DNA sequencing revealed that he has harbored compound heterozygous variants of the ATP6V0A4 gene, namely c.1363dupA (p.M455NfsX14) and c.2257C>T (p.Q753X), which were respectively inherited from his father and mother. Based on the guidelines from the American College of Medical Genetics and Genomics, both variants were classified as pathogenic (PVS1+PM3+PM2_Supporting). CONCLUSION The compound heterozygous variants of c.1363dupA (p.M455NfsX14) and c.2257C>T (p.Q753X) of the ATP6V0A4 gene probably underlay the pathogenesis of primary dRTA in this patient. Discovery of the c.2257C>T (p.Q753X) variant has also expanded the mutational spectrum of the ATP6V0A4 gene.
Humans ; Male ; Acidosis, Renal Tubular/genetics* ; Family ; Genomics ; Hypokalemia ; Infant

OBJECTIVE: To report the clinical and genetic characteristics of a rare case of Gitelman syndrome with comorbid Graves disease and ACTH-independent adrenocortical adenoma. METHODS: A patient who had presented at the Nanchong Central Hospital on December 21, 2020 was selected as the study subject. Clinical data of the patient was collected. Whole-exome sequencing was carried out on DNA extracted from peripheral venous blood samples from the patient and her family members. RESULTS: The patient, a 45-year-old woman, was found to have Graves disease, ACTH-independent Cushing syndrome, hypokalemia and hypomagnesemia following the discovery of an adrenal incidentaloma. MRI scan had revealed a 3.8 cm × 3.2 cm mass in the left adrenal gland. The mass was removed by surgery and confirmed as adrenocortical adenoma. DNA sequencing revealed that the patient and her sister have both harbored compound heterozygous variants of the SLC12A3 gene, namely c.1444-10(IVS11)G>A and c.179(exon1)C>T (p.T60M), which were respectively inherited from their father and mother. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the c.1444-10(IVS11)G>A and c.179(exon1)C>T (p.T60M) were respectively classified as a variant of uncertain significance (PM2_Supporting+PP3) and a likely pathogenic variant (PM3_Strong+PM1+PP3). CONCLUSION The conjunction of Gitelman syndrome with Graves disease and adrenal cortex adenoma is rather rare. The newly discovered c.1444-10(IVS11)G>A variant of the SLC12A3 gene, together with the heterozygous variant of c.179(exon1)C>T (p.T60M), probably underlay the pathogenesis in this patient.
Humans ; Female ; Middle Aged ; Gitelman Syndrome/genetics* ; Adrenocortical Adenoma ; Hypokalemia ; Graves Disease/genetics* ; Mothers ; Mutation ; Solute Carrier Family 12, Member 3

X-linked hypophosphatemia (XLH) is a rare disease of elevated fibroblast growth factor 23 (FGF23) production that leads to hypophosphatemia and impaired mineralization of bone and teeth. The clinical manifestations of XLH include a high prevalence of dental abscesses and periodontal disease, likely driven by poorly formed structures of the dentoalveolar complex, including the alveolar bone, cementum, dentin, and periodontal ligament. Our previous studies have demonstrated that sclerostin antibody (Scl-Ab) treatment improves phosphate homeostasis, and increases long bone mass, strength, and mineralization in the Hyp mouse model of XLH. In the current study, we investigated whether Scl-Ab impacts the dentoalveolar structures of Hyp mice. Male and female wild-type and Hyp littermates were injected with 25 mg·kg^-1 of vehicle or Scl-Ab twice weekly beginning at 12 weeks of age and euthanized at 20 weeks of age. Scl-Ab increased alveolar bone mass in both male and female mice and alveolar tissue mineral density in the male mice. The positive effects of Scl-Ab were consistent with an increase in the fraction of active (nonphosphorylated) β-catenin, dentin matrix protein 1 (DMP1) and osteopontin stained alveolar osteocytes. Scl-Ab had no effect on the mass and mineralization of dentin, enamel, acellular or cellular cementum. There was a nonsignificant trend toward increased periodontal ligament (PDL) attachment fraction within the Hyp mice. Additional PDL fiber structural parameters were not affected by Scl-Ab. The current study demonstrates that Scl-Ab can improve alveolar bone in adult Hyp mice.
Mice ; Male ; Female ; Animals ; Familial Hypophosphatemic Rickets/metabolism* ; Bone and Bones/metabolism* ; Tooth/metabolism* ; Periodontal Ligament/metabolism*

Elevated fibroblast growth factor 23 (FGF23) in X-linked hypophosphatemia (XLH) results in rickets and phosphate wasting, manifesting by severe bone and dental abnormalities. Burosumab, a FGF23-neutralizing antibody, an alternative to conventional treatment (phosphorus and active vitamin D analogs), showed significant improvement in the long bone phenotype. Here, we examined whether FGF23 antibody (FGF23-mAb) also improved the dentoalveolar features associated with XLH. Four-week-old male Hyp mice were injected weekly with 4 or 16 mg·kg^-1 of FGF23-mAb for 2 months and compared to wild-type (WT) and vehicle (PBS) treated Hyp mice (n = 3-7 mice). Micro-CT analyses showed that both doses of FGF23-mAb restored dentin/cementum volume and corrected the enlarged pulp volume in Hyp mice, the higher concentration resulting in a rescue similar to WT levels. FGF23-mAb treatment also improved alveolar bone volume fraction and mineral density compared to vehicle-treated ones. Histology revealed improved mineralization of the dentoalveolar tissues, with a decreased amount of osteoid, predentin and cementoid. Better periodontal ligament attachment was also observed, evidenced by restoration of the acellular cementum. These preclinical data were consistent with the retrospective analysis of two patients with XLH showing that burosumab treatment improved oral features. Taken together, our data show that the dentoalveolar tissues are greatly improved by FGF23-mAb treatment, heralding its benefit in clinics for dental abnormalities.
Humans ; Male ; Mice ; Animals ; Familial Hypophosphatemic Rickets/pathology* ; Fibroblast Growth Factor-23 ; Retrospective Studies ; Fibroblast Growth Factors/metabolism* ; Bone and Bones/metabolism* ; Phosphates/therapeutic use*