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Objectives: Vitamin D dependent rickets type 1A (VDDR1A) is a rare autosomal recessive condition due to inactivating mutation of CYP27B1 . It mimics clinically, biochemically and rediologically to nutritional and hypophosphatemic rickets. In developing countries like Pakistan, VDDR1A is often misdiagnosed as nutritional rickets or hypophosphatemic rickets due lack of free access to 1,25 (OH) 2 D level and genetic testing. This study was aimed to determine the clinical spectrum and diagnostic challenges of VDDR1A due to CYP27B1 mutation in developing countries., Methods: Retrospective review of all cases of VDDR1A due to CYP27B1 mutation over a period of two years presenting in the Pediatric Endocrine clinic of Hameed Latif Hospital, Lahore, Pakistan., Results: Six cases of VDDR1A (4 males) were identified. Mean age of clinical manifestation was 14 (9-24) months. Mean age of presentation to endocrine department was 5.5 (1.5-11.8) years. Growth failure and bony deformities were the most common presentation (n=6), followed by repeated diarrheas and abdominal distension (n=3) and recurrent fractures (n=1). All cases shared same biochemical profile of low/normal calcium, hypophosphatemia, raised alkaline phosphatase, raised PTH, normal/high 25(OH)D and tubular reabsorption of phosphate (TRP) <85%. Patients treated with calcitriol showed rapid healing as compared to those treated with 1-alfacalcidol., Conclusions: We should have a high index of suspicion of VDDR1A in rickets not responding to cholecalciferol therapy., (© 2022 Walter de Gruyter GmbH, Berlin/Boston.)

Objectives: XLHR in children with a Rickets Severity Score ≥2 can now be treated with the new antibody drug, Burosumab, which prevents bone deformities and increases gait endurance. This study illustrates the extent of complications in the traditional orthopedic treatment of XLHR. The impact of surgery and severity of complications in this patient population has not been systematically assessed before., Methods: The search strategy resulted in 215 studies and data were collected from 19 eligible studies and complications were categorized. Four medical charts of patients with XLHR at Aalborg University Hospital were assessed., Results: One complication occurred on average per surgical procedure for XLHR in the published literature. The 168 reported complications were categorized as follows: Type I (n=79): Complications with minimal intervention required and treatment goal still achieved, Type II (n=41): Complications with substantial change in treatment plan and treatment goal still achieved, Type IIIA (n=23): Complications with failure to achieve treatment goal and no new pathology or permanent sequelae, Type IIIB (n=25): Complications with failure to achieve treatment goal and/or new pathology or permanent sequelae., Conclusions: In average, one complication occurred per surgery and the severity of complications were substantial. The treatment goal was not achieved in 28% of surgeries whereof half of them resulted in permanent sequalae or new pathology. Our findings support the use of Burosumab for treatment of the skeletal changes in XLHR as the reported side-effects in Burosumab treatment appear negligible compared to the impact of surgeries and related complications (Imel EA, Glorieux FH, Whyte MP, Munns CF, Ward LM, Nilsson O, et al. Burosumab versus conventional therapy in children with X-linked hypophosphataemia: a randomised, active-controlled, open-label, phase 3 trial. Lancet 2019;393:2416-27). However, orthopedic surgery might still be needed for correcting deformities restricting activities of daily living in XLHR patients., (© 2022 Walter de Gruyter GmbH, Berlin/Boston.)

Objectives: Hereditary hypophosphatemic rickets (HR) is conventionally treated with phosphate and calcitriol. Exploring genotype and phenotypic spectrum of X-linked hypophosphatemic rickets (XLHR), focusing on short-term, long-term, and pubertal impact of conventional treatment was aimed., Methods: Sixteen patients from 12 unrelated families with HR were analyzed for phosphate regulating endopeptidase homolog X-linked ( PHEX) mutation. Initially Sanger sequencing analysis was performed. If PHEX mutation was not detected, multiplex ligation-dependent probe amplification (MLPA) was performed. If molecular defect was detected, first-degree relatives were analyzed. Thirteen patients (81%) and five first-degree relatives with XLHR were evaluated for genotype-phenotype or gender-phenotype correlation. Clinical characteristics and response to conventional treatment were determined retrospectively., Results: Nine different PHEX mutations were identified; four splice-site, three point mutations, and two single exon deletions. Four were novel mutations. Despite conventional treatment, median adult height was lower than median height on admission (-3.8 and -2.3 SDS, respectively), metabolic and radiographic recovery were not achieved, adherence was low (30%). Although mean adult height was better in compliant patients than noncompliants (-2.6 vs. -3.7 SDS, respectively), they were still short. Correlation between phenotype and genotype or gender could not be shown. Median phosphate decreased significantly throughout puberty (p=0.014). Median pubertal height was lower than prepubertal height (-4.4 vs. -3.6 SDS; respectively), pubertal growth spurt was not observed. Among five patients with a follow-up longer than five years, three had nephrocalcinosis (60%), two had hyperparathyroidism (40%), 4/6 (33%) required correction osteotomy., Conclusions: Conventional treatment appears to have limited effect on metabolic, clinical and radiographic recovery in XLHR. Metabolic control and growth worsened during puberty. Although, long-term adverse effects are yet to be seen, introduction of burosumab as first-line treatment may be an alternative after infancy., (© 2021 Walter de Gruyter GmbH, Berlin/Boston.)

Objectives: To identify a safe pathway for management and treatment of patients with X-linked hypophosphatemic rickets (XLH) during Covid-19 pandemic lockdown., Methods: Twenty-six patients with XLH (age 3.1-25.7 years) were enrolled in Pediatric Endocrine Unit; nine of them were receiving human monoclonal anti-fibroblast growth factor 23 antibody (burosumab) and 17 (pediatric patients, age 9.5-17.9 years, n=7; young-adult patients, age 20.1-25.7 years, n=10) received conventional treatment with inorganic oral phosphate salts and active vitamin D metabolites. A Covid-19 free pathway was addressed for XLH patients receiving burosumab treatment in hospital. XLH patients receiving conventional treatment were followed by phone calls, e-mails, or telemedicine., Results: All XLH patients receiving burosumab continued the scheduled follow-up and treatment; none of them was infected by Covid-19. Seven XLH patients out of 17 (41%) receiving conventional treatment showed some complication related to the disease itself or its treatment: periapical abscess with gingival fistula was diagnosed in five patients (three children and two young-adults) and treated with antibiotics with complete resolution; one child showed abdominal pain due to the administration of high doses of inorganic oral phosphate salts solved by reducing the dosage, and one child had severe legs pain during deambulation after orthopedic surgery solved with common analgesics., Conclusions: Covid-19 free pathway was safe and effective to manage XLH patients receiving burosumab. E-health technologies were useful methods to follow XLH patients receiving conventional treatment during Covid-19 pandemic lockdown., (© 2021 Walter de Gruyter GmbH, Berlin/Boston.)

Objectives: X-linked hypophosphatemic rickets (XLH) is a congenital fibroblast growth factor (FGF)23-related metabolic bone disease that is treated with active vitamin D and phosphate as conventional therapies. Complications of these therapies include nephrocalcinosis (NC) caused by excessive urine calcium and phosphate concentrations. Recently, an anti-FGF23 antibody, burosumab, was developed and reported to be effective in poorly-controlled or severe XLH patients. This study aimed to reveal the impact of switching treatments in relatively well-controlled XLH children with the Rickets Severity Scale less than 2.0., Methods: The effects of the two treatments in eight relatively well-controlled XLH children with a mean age of 10.4 ± 1.9 years were compared retrospectively for the same treatment duration (31 ± 11 months) before and after the baseline., Results: Actual doses of alfacalcidol and phosphate as conventional therapy were 150.9 ± 43.9 ng/kg and 27.5 ± 6.3 mg/kg per day, respectively. Renal echography revealed spotty NC in 8/8 patients, but no aggravation of NC was detected by switching treatments. Switching treatments increased TmP/GFR (p=0.002) and %TRP (p<0.001), and improved the high urine calcium/creatinine ratio to the normal range (p<0.001) although both treatments controlled disease markers equally. Additionally, low intact parathyroid hormone during conventional therapy was increased within the normal range by switching treatments., Conclusions: Our results suggest that a high dose of alfacalcidol was needed to control the disease, but it caused hypercalciuria and NC. We concluded that switching treatments in relatively well-controlled XLH children improved renal phosphate reabsorption and decreased urine calcium extraction, and may have the potential to prevent NC., (© 2021 Daisuke Harada et al., published by De Gruyter, Berlin/Boston.)

Objectives: Vitamin D dependent rickets type 1A (VDDR-1A) is a very rare autosomal recessive disorder caused by mutations in the CYP27B1 , which encodes vitamin D 1α-hydroxylase. We report the genetics and clinical manifestations of nine patients with VDDR-1A and compare our patients to other cases with the same mutations in the literature., Methods: The clinical presentations, clinical and laboratory findings and treatment modalities of the patients were evaluated retrospectively., Results: The mean age of the patients at the time of diagnosis was 39.9 months (range: 4.5-111). At the time of diagnosis, six patients had received stoss vitamin D therapy. Clinical findings related to rickets were obvious in seven patients and unclear in two patients. Except for one case, all patients had laboratory findings of rickets. A novel variant and four previously reported mutations in CYP27B1 were identified. The mean calcitriol and elemental calcium dose were 45.5 ng/kg/day (range: 20-70) and 75.6 mg/kg/day (range: 45-125), respectively., Conclusions: We found a novel compound heterozygous mutation consisting of a reported duplication [(p.F443Pfs*24 (c.1319&#95;1325 dup CCCACCC)] in exon 8 and a novel deletion [p.D507Efs*34 (c.1521 delC)] in exon 9. Our study suggests that the clinical manifestations and laboratory findings of the patients with VDDR1A are variable even among the patients with the same mutation., (© 2021 Walter de Gruyter GmbH, Berlin/Boston.)

Background: Vitamin D regulates the concentrations of calcium and phosphate in blood and promotes the growth and remodeling of bones. The circulating active form of vitamin D, 1,25-dihydroxyvitamin D, binds to the vitamin D receptor (VDR), which heterodimerizes with the retinoid X receptor to regulate the expression of target genes. Inactivating mutations in the VDR gene cause hereditary vitamin D-resistant rickets (HVDRR), a rare disorder characterized by an early onset of rickets, growth retardation, skeletal deformities, hypocalcemia, hypophosphatemia and secondary hyperparathyroidism, and in some cases alopecia., Methods: We describe eight new HVDRR patients from four unrelated consanguineous families. The VDR gene was sequenced to identify mutations. The management of patients over a period of up to 11 years following the initial diagnosis is assessed., Results: Although all patients exhibit main features of HVDRR and carry the same c.885C>A (p.Y295*) loss of function mutation in the VDR gene, there was heterogeneity of the manifestations of HVDRR-associated phenotypes and developmental milestones. These eight patients were successfully treated over a period of 11 years. All clinical symptoms were improved except alopecia., Conclusions: The study concludes that VDR sequencing and laboratory tests are essential to confirm HVDRR and to assess the effectiveness of the treatment.

Hereditary vitamin D-resistant rickets (HVDRR) is an autosomal recessive disorder characterized by end-organ resistance to 1α,25-dihydroxyvitamin D3 (1,25D3). Clinically, the syndrome is recognized by severe early onset rickets with bowing of the lower extremities, short stature, and often alopecia. Here, we report a case series on three siblings who had HVDRR with varied clinical findings.

Objective: To study the vitamin D receptor (VDR) gene in five Egyptian patients with severe rickets and the clinical features of hereditary vitamin D-resistant rickets, including hypocalcemia, hypophosphatemia, total alopecia, and elevated serum levels of 1,25-dihydroxyvitamin D., Study Design: We amplified and sequenced DNA samples from blood from the patients, their parents, and available family members., Results: DNA sequence analyses of the VDR gene showed three novel mutations (p.Y295X, p.R343C, and p.R391H) and a previously reported one (p.R30X) in four patients, whereas no mutation was found in one patient. Mutations cosegregated perfectly with affected individuals in all families, and did not exist in unaffected family members or 200 ethnically matched chromosomes., Conclusion: Three novel deleterious mutations in the VDR ligand-binding domain were identified, which are expected to render the VDR nonfunctional. Successful treatment with frequent high doses of oral calcium and calcidol was evident in all patients; however, hair growth occurred only in one patient.

We report a girl who presented with clinical and biochemical features of hypophosphatemic rickets. Mutational analysis detected a heterozygous nonsynonymous sequence variation in exon 11 of the PHEX gene (NM&#95;000444.4:c.1216T>C, NP&#95;000435.3:p.Cys406Arg). This previously undescribed PHEX mutation is probably the cause of renal phosphate wasting in our patient that resulted in rickets.

Wilson's disease rarely presents with isolated neurological complaints without any hepatic involvement. Refractory rickets with Wilson's disease has been infrequently reported in literature. We are reporting a case of isolated neurological Wilson's disease associated with refractory rickets which on complete evaluation was diagnosed as familial hypophosphatemic rickets.

We describe four patients (two pairs of children from two unrelated kindreds) from a Greek island, suffering from hereditary vitamin D-resistant rickets (HVDRR) with alopecia. There were two different homozygous mutations in the vitamin D receptor (VDR) gene of the affected members of the two kindreds that resulted in a truncated or missing receptor. The disorder began in early infancy with similar clinical, biochemical and radiological findings in all four patients, namely, alopecia (which provided the initial diagnostic evidence for HVDRR), rachitic deformities, hypocalcemia, hypophosphatemia, secondary hyperparathyroidism, and elevated serum levels of 1,25-dihydroxyvitamin D; however, the patients of kindred B had a more severe clinical expression. Treatment options include oral or intravenous calcium and active vitamin D metabolites. The response varies widely in different cases. Our patients were initially treated with high doses of 1alpha(OH)D3 and oral calcium supplementation. Kindred A patients had a satisfactory response to this regimen, while kindred B patients presented clinical and biochemical improvement when 1alpha(OH)D3 was changed to 1,25(OH)2D3. In the older patients of each kindred, treatment requirements gradually decreased during puberty, and therapy was finally discontinued before adulthood.