Tebben, Peter

Abstract Context The ketogenic diet is associated with progressive skeletal demineralization, hypercalciuria, and nephrolithiasis. Acute hypercalcemia has been described as a newly recognized complication of this treatment. Objective To describe the clinical characteristics of acute hypercalcemia in children on the ketogenic diet through analysis of the presentation, response to treatment, and natural history in a large cohort of patients. Design A multicenter case series was performed including children who developed acute hypercalcemia while treated with the ketogenic diet. Information on clinical presentation, treatment, and course of this complication was collated centrally. Results There were 14 patients (median (range) age 6.3 (0.9 to 18) years) who developed hypercalcemia 2.1 (range, 0.2-12) years after starting the ketogenic diet. All had low levels of parathyroid hormone and levels of 1,25-dihydroxyvitamin D were low in all except one. Seven (50%) had impaired renal function at presentation. All except the 2 oldest had low alkaline phosphatase levels for age. Once normocalcemia was achieved, hypercalcemia recurred in only 2 of these patients over observation of up to 9.8 years. One patient discontinued the ketogenic diet prior to achieving normocalcemia while 4 more stopped the diet during follow-up after resolution of hypercalcemia. Conclusions Ketotic hypercalcemia can occur years after starting the ketogenic diet, especially in the setting of renal impairment. The mechanism is unknown but appears to be due to reduced osteoblast activity and impaired bone formation. We recommend close attention to optimizing bone health in these children, and screening for the development of ketotic hypercalcemia.

AbstractBranchio‐oto‐renal spectrum disorder (BORSD) is a rare autosomal dominant condition characterized by ear abnormalities with hard of hearing/deafness, second branchial arch malformations and renal anomalies. Pathogenic variations in EYA1 gene are found in the majority of clinically diagnosed individuals with BORSD. We describe an infant with BORSD related to a paternally inherited heterozygous pathogenic variation in EYA1 gene presenting with poor growth and hypoglycemia due to growth hormone deficiency. Magnetic resonance imaging revealed a diminutive pituitary gland and morphologically abnormal sella. Upon initiation of growth hormone therapy, the hypoglycemia resolved and catch up growth ensued. Pituitary abnormalities have not been reported previously in patients with BORSD. The zebrafish ortholog of eya1 is important for the development of adenohypophysis, suggesting that this patient's growth hormone deficiency and pituitary abnormality are part of BORSD. Inclusion of screening for pituitary hormone deficiency and pituitary imaging should be considered as a part of surveillance in patients with BORSD.

AbstractPrader–Willi syndrome (PWS) is a prototypic genetic condition related to imprinting. Causative mechanisms include paternal 15q11‐q13 deletion, maternal chromosome 15 uniparental disomy (UPD15), Prader–Willi Syndrome/Angelman Syndrome (PWS/AS) critical region imprinting defects, and complex chromosomal rearrangements. Maternal UPD15‐related PWS poses risks of concomitant autosomal recessive (AR) disorders when the mother carries a pathogenic variant in one of the genes on chromosome 15 associated with autosomal recessive inherited disease. Co‐occurrence of autosomal recessive conditions in the setting of UPD leads to increased complexity of the clinical phenotype, and may delay the diagnosis of PWS. We report a patient with PWS and associated congenital ichthyosis due to maternal UPD15, and a homozygous novel pathogenic variant in ceramide synthase 3 (CERS3). We also review the literature of associated disorders reported in the setting of maternal UPD15‐related PWS and provide a summary of the previously described CERS3 variants. This represents the second case of autosomal recessive congenital ichthyosis (ARCI) in the setting of PWS and UPD15. There needs to be a high index of suspicion of this genetic mechanism when there is unexpected phenotype or evolution of the clinical course in a patient with PWS.

Abstract Background (+)‐Epicatechin (EPI) induces mitochondrial biogenesis and antioxidant metabolism in muscle fibers and neurons. We aimed to evaluate safety and efficacy of (+)‐EPI in pediatric subjects with Friedreich's ataxia (FRDA). Methods This was a phase II, open‐label, baseline‐controlled single‐center trial including 10 participants ages 10 to 22 with confirmed FA diagnosis. (+)‐EPI was administered orally at 75 mg/d for 24 weeks, with escalation to 150 mg/d at 12 weeks for subjects not showing improvement of neuromuscular, neurological or cardiac endpoints. Neurological endpoints were change from baseline in Friedreich's Ataxia Rating Scale (FARS) and 8‐m timed walk. Cardiac endpoints were changes from baseline in left ventricular (LV) structure and function by cardiac magnetic resonance imaging (MRI) and echocardiogram, changes in cardiac electrophysiology, and changes in biomarkers for heart failure and hypertrophy. Results Mean FARS/modified (m)FARS scores showed nonstatistically significant improvement by both group and individual analysis. FARS/mFARS scores improved in 5/9 subjects (56%), 8‐m walk in 3/9 (33%), 9‐peg hole test in 6/10 (60%). LV mass index by cardiac MRI was significantly reduced at 12 weeks ( P = .045), and was improved in 7/10 (70%) subjects at 24 weeks. Mean LV ejection fraction was increased at 24 weeks ( P = .008) compared to baseline. Mean maximal septal thickness by echocardiography was increased at 24 weeks ( P = .031). There were no serious adverse events. Conclusion (+)‐EPI was well tolerated over 24 weeks at up to 150 mg/d. Improvement was observed in cardiac structure and function in subset of subjects with FRDA without statistically significant improvement in primary neurological outcomes. Synopsis A (+)‐epicatechin showed improvement of cardiac function, nonsignificant reduction of FARS/mFARS scores, and sustained significant upregulation of muscle‐regeneration biomarker follistatin.

In this article, we describe the long-term outcomes of children who were previously reported to have developed hypophosphatemic bone disease in association with elemental formula use. An extended chart review allowed for an updated report of 34 children with regard to severity/duration of bone disease, extent of recovery, and time to correction using radiology reports and biochemical data. After implementation of formula change and/or phosphate supplementation, we found that serum phosphorus concentration increased and serum alkaline phosphatase activity decreased in all patients, normalizing by 6.6 ± 4.0 (mean ± SD) months following diagnosis. The decrease in serum alkaline phosphatase from diagnosis to the time of correction was moderately correlated with the concurrent increase in serum phosphorus ( R = 0.48, P < .05). Age at diagnosis significantly correlated with time to resolution ( R = 0.51, P = .01). This study supports the earlier report that bone disease associated with hypophosphatemia during elemental formula use responds to formula change and/or phosphate supplementation.

Abstract Background The objective of this study was to evaluate the age at onset and frequency of individual pituitary hormone deficiencies (PHDs) in optic nerve hypoplasia (ONH). Methods We performed a retrospective chart review of patients ≤21 years of age evaluated between 1996 and 2014. Patients were included if they had: (1) ONH diagnosed by an ophthalmologist and/or magnetic resonance imaging (MRI), (2) documentation of pituitary hormone function on at least two separate occasions and (3) at least one PHD documented or a midline abnormality of the brain on MRI. Results Thirty-two patients (18 females, 14 males) were included (median age, 8 years [range, 1.1–21.0 years]). All patients had ONH (bilateral, n = 31; unilateral, n = 1) and at least one midline abnormality of the brain. At least one PHD was present in 75% of patients (n = 24). The remaining 25% of patients (n = 8) did not develop any PHD at least until the last follow-up (<2–8.6 years of follow-up), despite the presence of ONH and a midline abnormality of the brain. The median age (years) at diagnosis of antidiuretic hormone (ADH), thyroid-stimulating hormone (TSH), adrenocorticotropic hormone (ACTH) and growth hormone (GH) deficiencies was 0.5, 0.6, 0.7 and 1.6, respectively. Twenty-three percent of all PHDs were identified during the neonatal period, 56% by 12 months and 72% by 36 months of age. The latest age at diagnosis of GH, ACTH and TSH deficiencies was 9.6, 9.9 and 12.6 years, respectively. Conclusions The majority of the PHDs in ONH develop within the first 3 years of life. We propose evaluation for endocrinopathies at the time of diagnosis of ONH, with repeat assessment for new deficiencies every 3–4 months until age 3 years and at least semi-annually until growth and puberty are complete.

AbstractRationale, aims, and objectivesWaist circumference (WC) and waist‐to‐height ratio (WHtR) are superior surrogate markers of central obesity than body mass index. However, WC is not measured routinely in paediatric clinics. The objective of this study was to implement measurement of WC during routine assessment of children in an ambulatory outpatient clinic setting and subsequent dissemination of cardiometabolic risk counselling in children with central obesity (defined as WHtR ≥0.5).MethodProspective cohort of patients aged 6 to 20 years. Study period was divided into three phases: baseline (3 months), process improvement (2 months), and implementation (6 months). Define‐Measure‐Analyse‐Improve‐Control (DMAIC) strategy was applied. Measurement of WC was implemented as a component of the physical examination in patients. Outcome measures were (1) improvement in frequency of WC measurement and (2) utilization of WHtR in cardiometabolic risk counselling.ResultsWaist circumference was not measured in any patient during baseline phase (n = 551). During process improvement phase, of the total 347 patients, WC was measured in 35% vs target of 30%. In the implementation phase, WC was measured in 37% patients (365 out of 964). Of these 365 patients, 175 (48%) had elevated WHtR, and 73% of them (n = 128) were counselled about their increased cardiometabolic risk.ConclusionsApplication of an evidence‐based DMAIC protocol led to significant improvement in assessment for central obesity in an ambulatory clinic practice and appropriate counselling regarding cardiometabolic risk reduction in children and adolescents with central obesity over an 8‐month period. Meticulous planning and execution, frequent reinforcement, and integrating feedback from the involved multi‐disciplinary team were important factors in successful implementation of this quality improvement project.

SummaryBackgroundThere is a lack of consensus on the cardiometabolic consequences of mild subclinical hypothyroidism (SCH) among children. The objective of the current study was to compare lipid profiles in children with mild SCH with those of euthyroid children.Study DesignRetrospective medical record review.PatientsChildren (ages 2‐18 years) who had undergone simultaneous measurement of TSH, free thyroxine (T4) and lipids. Lipids in children with mild SCH (TSH 5‐<10 mIU/L and normal free T4, n = 228) were compared with those in euthyroid children (n = 1215).ResultsTSH level was positively associated with total cholesterol and nonhigh density lipoprotein (non‐HDL) cholesterol [β 0.05(0.03‐0.08), P < .0001 and β 0.05(0.03‐0.08), P < .0001, respectively]. Total cholesterol was significantly higher in children and adolescents with mild SCH compared with euthyroid children (4.43 ± 1.14 mmol/L vs 4.2 ± 0.85 mmol/L, P = .0005). Similarly, non‐HDL cholesterol level was also higher in children with mild SCH relative to euthyroid children (3.08 ± 1.14 mmol/L vs 2.91 ± 0.8 mmol/L, P = .001). The adjusted odds ratio of having elevated total cholesterol and elevated non‐HDL cholesterol was greater in children with mild SCH compared with euthyroid children (OR 1.88, 95% CI; 1.28‐2.73; P = .001 and 1.72, 95% CI 1.2‐2.5; P = .003, respectively). The presence of thyroid autoimmunity was not associated with higher rates of dyslipidaemia.ConclusionsMild SCH in children and adolescents was associated with higher rates of elevated total cholesterol and elevated non‐HDL cholesterol. Randomized placebo controlled studies are warranted to determine if treatment of mild SCH in children leads to improvement in lipid profile.

Abstract Hypercalcemia occurs in up to 4% of the population in association with malignancy, primary hyperparathyroidism, ingestion of excessive calcium and/or vitamin D, ectopic production of 1,25-dihydroxyvitamin D [1,25(OH)2D], and impaired degradation of 1,25(OH)2D. The ingestion of excessive amounts of vitamin D3 (or vitamin D2) results in hypercalcemia and hypercalciuria due to the formation of supraphysiological amounts of 25-hydroxyvitamin D [25(OH)D] that bind to the vitamin D receptor, albeit with lower affinity than the active form of the vitamin, 1,25(OH)2D, and the formation of 5,6-trans 25(OH)D, which binds to the vitamin D receptor more tightly than 25(OH)D. In patients with granulomatous disease such as sarcoidosis or tuberculosis and tumors such as lymphomas, hypercalcemia occurs as a result of the activity of ectopic 25(OH)D-1-hydroxylase (CYP27B1) expressed in macrophages or tumor cells and the formation of excessive amounts of 1,25(OH)2D. Recent work has identified a novel cause of non-PTH-mediated hypercalcemia that occurs when the degradation of 1,25(OH)2D is impaired as a result of mutations of the 1,25(OH)2D-24-hydroxylase cytochrome P450 (CYP24A1). Patients with biallelic and, in some instances, monoallelic mutations of the CYP24A1 gene have elevated serum calcium concentrations associated with elevated serum 1,25(OH)2D, suppressed PTH concentrations, hypercalciuria, nephrocalcinosis, nephrolithiasis, and on occasion, reduced bone density. Of interest, first-time calcium renal stone formers have elevated 1,25(OH)2D and evidence of impaired 24-hydroxylase-mediated 1,25(OH)2D degradation. We will describe the biochemical processes associated with the synthesis and degradation of various vitamin D metabolites, the clinical features of the vitamin D-mediated hypercalcemia, their biochemical diagnosis, and treatment.