Neurofibromatosis type 1 (NF1) is a multisystem disorder characterized by progressive manifestations, which is inherited in an autosomal dominant manner. The majority of patients with NF1 experience a diffuse, significant reduction in bone mass over time, with osteoporosis, osteopenia in the absence of severe scoliosis, or gross bone deformities. This study aimed to determine the bone mineral density (BMD) status, evaluate bone metabolism, and to determine the relevant factors in children with NF1.
The study population included 33 pediatric NF1 patients (20 males and 13 females). Bone metabolic markers, such as total calcium, phosphorus, magnesium, alkaline phosphatase, parathyroid hormone, and 25-OH vitamin D, the urinary calcium/creatine ratio were measured. In addition, BMD was measured at both the lumbar spine (LS) and the femoral neck in all the patients.
All the patients had a low 25-OH vitamin D level, but it was significantly lower in the females than in the males (p<0.009). Overall, 18.2% of the patients had skeletal abnormalities. The lumbar Z-score was ≤2 in 21.2% of the patients, whereas the femoral neck Z-score was ≤2 in 9.1%. The urinary calcium/creatine ratio was significantly higher in the female than in the male patients (p<0.027). In all, six patients had skeletal abnormalities.
It is widely known that bone mineral metabolism markers and BMD are significantly affected in NF1 patients; however, the present study did not identify any effective parameters that could be used to predict skeletal abnormalities, or diagnose early osteoporosis and osteopenia in pediatric NF1 patients.
We would like to thank all patients and families for their participation in this study. We also thank Fehan Elmali for statistical analysis.
Author contributions: PHG conceived the study, BVN, GH, and PH reviewed the literature, PHG, BVN, GH, PH, CM and KS were involved in patients care, including the process of procedure and routine clinical follow-up, AA, BF made helpful collection of data, PHG and AA performed literature review and written manuscript. BF, CM, and KS reviewed the manuscript. All authors were responsible for patient management. All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.
Research funding: None declared.
Employment or leadership: None declared.
Honorarium: None declared.
Competing interests: The funding organization(s) played no role in the study design; in the collection, analysis, and interpretation of data; in the writing of the report; or in the decision to submit the report for publication.
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