Objective To study the diagnosis,treatment,and complications of hypophosphatemic rickets(HR)in children,explore effectiveness evaluation indicators for the disease,and understand the pattern in height growth among these patients.Methods A retrospective analysis of the initial clinical data and five-year follow-up data of 85 children with HR treated at Children's Hospital of Nanjing Medical University from January 2008 to December 2022.Results Among the 85 children with HR,there were 46 males(54%)and 39 females(46%).The age at initial diagnosis ranged from 6 months to 13 years and 9 months,with a median age of 2.75 years.The average height standard deviation score was-2.0±1.1.At initial diagnosis,children exhibited reduced blood phosphate levels and elevated alkaline phosphatase(ALP),with 99%(84/85)presenting with lower limb deformities.The positive rate for PHEX gene mutations was 93%(55/59).One year post-treatment,there was a significant reduction in ALP levels and the gap between the lower limbs(P<0.05).The fastest height growth occurred in the first year after treatment,at 8.23 cm/year,with a peak height velocity(PHV)phase lasting about two years during puberty.The height increased by 9-20 cm in male children during the PHV stage and 10-15 cm in female children.Major complications included nephrocalcinosis and hyperparathyroidism.The incidence rate of nephrocalcinosis in the first year after treatment was 55%(22/40),which increased with the duration of the disease(P<0.001);an increased urinary phosphate/creatinine ratio was positively associated with a higher risk of nephrocalcinosis(OR=1.740,P<0.001).The incidence of hyperparathyroidism in the first year after treatment was 64%(27/42).Conclusions For children presenting with lower limb deformities,short stature,and slow growth,early testing for blood levels of phosphate,calcium,and ALP,along with imaging examinations of the lower limbs,can aid in the early diagnosis of HR.Genetic testing may be utilized for definitive confirmation when necessary.ALP combined with improvements in skeletal deformities and annual height growth can serve as indicators of therapeutic effectiveness for HR.Compared to normal children,children with HR demonstrate a lower height increase during the PHV phase,necessitating close follow-up and timely adjustment of treatment plans

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*

Humans ; Polycystic Kidney, Autosomal Recessive/genetics*