Endocrine Abstracts

JOINT3731

Background: Rickets is a metabolic bone disease characterized by inadequate mineralization of growing bone tissue due to deficiency of calcium, phosphorus, vitamin D or resistance to vitamin D. Genetic causes of rickets are rare and accounts for 13% of all rickets cases. Genetic rickets can be divided into two groups: vitamin D-dependent rickets and hypophosphatemic rickets (HR). All of them present similar clinical manifestations of hypocalcemia and/or rickets. This study aimed to evaluate the clinical, laboratory and genetic features and long-term follow-up of the patients diagnosed with genetic rickets.

Materials and Methods: The study included patients diagnosed with genetic rickets between 2010 and 2024 in our clinic. Relevant data were collected retrospectively from medical records. The patients were evaluated in terms of clinical, laboratory, and genetic characteristics.

Results: Fifteen patients were included in the study. Eight of the patients (53. 3%) were male, and seven (46. 7%) were female. Of the patients, six had Vitamin D-dependent rickets type 1 (VDDR1), two had Vitamin D-dependent rickets type 2 (VDDR2), and seven had Hypophosphatemic Rickets (HPR). The most common presentation was leg deformities; followed by delayed walking, growth retardation, alopecia, delayed dental development and bone pain. The mean age at presentation was 3. 5 ± 3. 1 years. Physical examination findings included JOINT widening (40%), genu varum (33. 3%), short stature (33. 3%), genu valgum (26. 7%), rachitic rosary (26. 7%), caput quadratum (6. 7%), pectus carinatum (6. 7%), and frontal bossing (6. 7%). The diagnosis of all the cases with VDDR1 was confirmed by demonstration of the variant in the CYP27B1 gene. One of the VDDR2 cases showed a variant in the VDR gene, while genetic analyses could not be performed in the other. Six patients with HPR had variants in the PHEX, and one had variant in the CLCN5. The mean follow-up period for the patients was 77. 9 months. The mean final height of the four patients, who reached final height, was 142. 07 ± 11. 19 cm (129-155 cm). No complications were observed in any of the patients during long-term follow-up.

Conclusion: This study provides valuable insights into the clinical and laboratory characteristics, as well as long-term follow-up outcomes, of 15 patients diagnosed with genetic rickets. The findings are important for expand the knowledge and increase the awareness of this rare condition and for encouraging further research in this area.

Keywords: genetic rickets, CYP27B1, VDR, PHEX, CLCN5