Nathalie Alos

Mutations in Prokineticin 2 and Prokineticin receptor 2genes in Human Gonadotrophin-Releasing Hormone Deficiency: Molecular Genetics and Clinical Spectrum

CONTEXT Mice deficient in prokineticin 2(PROK2) and prokineticin receptor2 (PROKR2) exhibit variable olfactory bulb dysgenesis and GnRH neuronal migration defects reminiscent of human GnRH deficiency. OBJECTIVES We aimed to screen a large cohort of patients with Kallmann syndrome (KS) and normosmic idiopathic hypogonadotropic hypogonadism (IHH) for mutations in PROK2/PROKR2, evaluate their prevalence, define the genotype/phenotype relationship, and assess the functionality of these mutant alleles in vitro. DESIGN Sequencing of the PROK2 and PROKR2 genes was performed in 170 KS patients and 154 nIHH. Mutations were examined using early growth response 1-luciferase assays in HEK 293 cells and aequorin assays in Chinese hamster ovary cells. RESULTS Four heterozygous and one homozygous PROK2 mutation (p.A24P, p.C34Y, p.I50M, p.R73C, and p.I55fsX1) were identified in five probands. Four probands had KS and one nIHH, and all had absent puberty. Each mutant peptide impaired receptor signaling in vitro except the I50M. There were 11 patients who carried a heterozygous PROKR2 mutation (p.R85C, p.Y113H, p.V115M, p.R164Q, p.L173R, p.W178S, p.S188L, p.R248Q, p.V331M, and p.R357W). Among them, six had KS, four nIHH, and one KS proband carried both a PROKR2 (p.V115M) and PROK2 (p.A24P) mutation. Reproductive phenotypes ranged from absent to partial puberty to complete reversal of GnRH deficiency after discontinuation of therapy. All mutant alleles appear to decrease intracellular calcium mobilization; seven exhibited decreased MAPK signaling, and six displayed decreased receptor expression. Nonreproductive phenotypes included fibrous dysplasia, sleep disorder, synkinesia, and epilepsy. Finally, considerable variability was evident in family members with the same mutation, including asymptomatic carriers. CONCLUSION Loss-of-function mutations in PROK2 and PROKR2 underlie both KS and nIHH.

Advanced Vertebral Fracture among Newly Diagnosed Children with Acute Lymphoblastic Leukemia: Results of the Canadian STeroid-associated Osteoporosis in the Pediatric Population (STOPP) Research Program

Vertebral compression is a serious complication of childhood acute lymphoblastic leukemia (ALL). The prevalence and pattern of vertebral fractures, as well as their relationship to BMD and other clinical indices, have not been systematically studied. We evaluated spine health in 186 newly diagnosed children (median age, 5.3 yr; 108 boys) with ALL (precursor B cell: N = 167; T cell: N = 19) who were enrolled in a national bone health research program. Patients were assessed within 30 days of diagnosis by lateral thoraco‐lumbar spine radiograph, bone age (also used for metacarpal morphometry), and BMD. Vertebral morphometry was carried out by the Genant semiquantitative method. Twenty‐nine patients (16%) had a total of 75 grade 1 or higher prevalent vertebral compression fractures (53 thoracic, 71%; 22 lumbar). Grade 1 fractures as the worst grade were present in 14 children (48%), 9 patients (31%) had grade 2 fractures, and 6 children (21%) had grade 3 fractures. The distribution of spine fracture was bimodal, with most occurring in the midthoracic and thoraco‐lumbar regions. Children with grade 1 or higher vertebral compression had reduced lumbar spine (LS) areal BMD Z‐scores compared with those without (mean ± SD, −2.1 ± 1.5 versus −1.1 ± 1.2; p < 0.001). LS BMD Z‐score, second metacarpal percent cortical area Z‐score, and back pain were associated with increased odds for fracture. For every 1 SD reduction in LS BMD Z‐score, the odds for fracture increased by 80% (95% CI: 10–193%); the presence of back pain had an OR of 4.7 (95% CI: 1.5–14.5). These results show that vertebral compression is an under‐recognized complication of newly diagnosed ALL. Whether the fractures will resolve through bone growth during or after leukemia chemotherapy remains to be determined.

Incident vertebral fractures among children with rheumatic disorders 12 months after glucocorticoid initiation: a national observational study.

To determine the frequency of incident vertebral fractures (IVF) 12 months after glucocorticoid (GC) initiation in children with rheumatic diseases and to identify children at higher risk.

High Incidence of Vertebral Fractures in Children With Acute Lymphoblastic Leukemia 12 Months After the Initiation of Therapy

PURPOSE Vertebral fractures due to osteoporosis are a potential complication of childhood acute lymphoblastic leukemia (ALL). To date, the incidence of vertebral fractures during ALL treatment has not been reported. PATIENT AND METHODS We prospectively evaluated 155 children with ALL during the first 12 months of leukemia therapy. Lateral thoracolumbar spine radiographs were obtained at baseline and 12 months. Vertebral bodies were assessed for incident vertebral fractures using the Genant semiquantitative method, and relevant clinical indices such as spine bone mineral density (BMD), back pain, and the presence of vertebral fractures at baseline were analyzed for association with incident vertebral fractures. RESULTS Of the 155 children, 25 (16%; 95% CI, 11% to 23%) had a total of 61 incident vertebral fractures, of which 32 (52%) were moderate or severe. Thirteen (52%) of the 25 children with incident vertebral fractures also had fractures at baseline. Vertebral fractures at baseline increased the odds of an incident fracture at 12 months by an odds ratio of 7.3 (95% CI, 2.3 to 23.1; P = .001). In addition, for every one standard deviation reduction in spine BMD Z-score at baseline, there was 1.8-fold increased odds of incident vertebral fracture at 12 months (95% CI, 1.2 to 2.7; P = .006). CONCLUSION Children with ALL have a high incidence of vertebral fractures after 12 months of chemotherapy, and the presence of vertebral fractures and reductions in spine BMD Z-scores at baseline are highly associated clinical features.

Pamidronate: Treatment for Severe Hypercalcemia in Neonatal Subcutaneous Fat Necrosis

Background: Subcutaneous fat necrosis (SCFN) of the newborn is an uncommon disorder that occurs in the first weeks of life after foetal distress. It can be complicated by potentially life-threatening hypercalcemia. Treatments of hypercalcemia have included hydration, furosemide and corticosteroids. Only one report has described the use of intravenous bisphosphonates for this condition. We propose that pamidronate could be the first line therapy for severe hypercalcemia in SCFN. Patients and Results: Four newborns presented between 2001 and 2004 with SCFN complicated by severe hypercalcemia. At diagnosis, ionized calcium levels were higher than 1.4 mmol/l and were associated with high urinary calcium/creatinine ratios and high 1,25-dihydroxyvitamin D levels. Despite treatment with IV fluids, low calcium diet and furosemide, calcium levels remained high. The patients were given 3–4 doses (0.25–0.50 mg/kg/dose) of pamidronate. Urinary calcium/creatinine ratios and calcium levels decreased within 48–96 h. 1,25-dihydroxyvitamin D levels normalized with resolution of the skin lesions. No persistent nephrocalcinosis was observed. Conclusion: Pamidronate is effective, well-tolerated in the short-term and obviates the need for prolonged treatment with furosemide and corticosteroids. To prevent nephrocalcinosis, pamidronate might be considered as first line treatment for severe hypercalcemia in SCFN.

Incident vertebral fractures and risk factors in the first three years following glucocorticoid initiation among pediatric patients with rheumatic disorders

Vertebral fractures are an important yet underrecognized manifestation of osteoporosis in children with chronic, glucocorticoid‐treated illnesses. Our goal was to determine the incidence and clinical predictors of vertebral fractures in the 3 years following glucocorticoid initiation among pediatric patients with rheumatic disorders. Incident vertebral fractures were evaluated according to the Genant semiquantitative method on lateral radiographs at baseline and then annually in the 3 years following glucocorticoid initiation. Extended Cox models were used to assess the association between vertebral fractures and clinical risk predictors. A total of 134 children with rheumatic disorders were enrolled in the study (mean ± standard deviation (SD) age 9.9 ± 4.4 years; 65% girls). The unadjusted vertebral fracture incidence rate was 4.4 per 100 person‐years, with a 3‐year incidence proportion of 12.4%. The highest annual incidence occurred in the first year (6.0%; 95% confidence interval (CI) 2.9% to 11.7%). Almost one‐half of the patients with fractures were asymptomatic. Every 0.5 mg/kg increase in average daily glucocorticoid (prednisone equivalents) dose was associated with a twofold increased fracture risk (hazard ratio (HR) 2.0; 95% CI 1.1 to 3.5). Other predictors of increased vertebral fracture risk included: (1) increases in disease severity scores between baseline and 12 months; (2) increases in body mass index Z‐scores in the first 6 months of each 12‐month period preceding the annual fracture assessment; and (3) decreases in lumbar spine bone mineral density Z‐scores in the first 6 months of glucocorticoid therapy. As such, we observed that a clinically significant number of children with rheumatic disorders developed incident vertebral fractures in the 3 years following glucocorticoid initiation. Almost one‐half of the children were asymptomatic and thereby would have been undiagnosed in the absence of radiographic monitoring. In addition, discrete clinical predictors of incident vertebral fractures were evident early in the course of glucocorticoid therapy.

Incident Vertebral Fractures in Children With Leukemia During the Four Years Following Diagnosis

OBJECTIVES The purpose of this article was to determine the incidence and predictors of vertebral fractures (VF) during the 4 years after diagnosis in pediatric acute lymphoblastic leukemia (ALL). PATIENTS AND METHODS Children were enrolled within 30 days of chemotherapy initiation, with incident VF assessed annually on lateral spine radiographs according to the Genant method. Extended Cox models were used to assess the association between incident VF and clinical predictors. RESULTS A total of 186 children with ALL completed the baseline evaluation (median age, 5.3 years; interquartile range, 3.4-9.7 years; 58% boys). The VF incidence rate was 8.7 per 100 person-years, with a 4-year cumulative incidence of 26.4%. The highest annual incidence occurred at 12 months (16.1%; 95% confidence interval [CI], 11.2-22.7), falling to 2.9% at 4 years (95% CI, 1.1-7.3). Half of the children with incident VF had a moderate or severe VF, and 39% of those with incident VF were asymptomatic. Every 10 mg/m(2) increase in average daily glucocorticoid dose (prednisone equivalents) was associated with a 5.9-fold increased VF risk (95% CI, 3.0-11.8; P < .01). Other predictors of increased VF risk included VF at diagnosis, younger age, and lower spine bone mineral density Z-scores at baseline and each annual assessment. CONCLUSIONS One quarter of children with ALL developed incident VF in the 4 years after diagnosis; most of the VF burden was in the first year. Over one third of children with incident VF were asymptomatic. Discrete clinical predictors of a VF were evident early in the patients clinical course, including a VF at diagnosis.

Do estrogens impact adolescent idiopathic scoliosis

Recent discoveries in the pathogenesis of adolescent idiopathic scoliosis (AIS) indicate that various hormones, especially estrogens, have a role in its onset and development. This role for estrogen seems possible because of its interaction with factors that influence the development and progression of this spinal deformity. Additionally, estrogens impact bone remodeling and growth, as well as bone acquisition, all of which are affected in AIS. Despite the fact that estrogens are not causative factors of AIS, they could impact the progression of spinal deformity by interacting with factors that modulate bone growth, biomechanics and structure. Thus, clarifying the role of estrogens is essential for understanding how AIS evolves during skeletal growth and for the development of new therapeutic interventions.

Effectiveness of pamidronate as treatment of symptomatic osteonecrosis occurring in children treated for acute lymphoblastic leukemia.

Osteonecrosis (ON) is a severe complication of acute lymphoblastic leukemia (ALL) treatments. Recent studies suggest that bisphosphonates might reduce pain and loss of motor function in patients with ON. We assessed the effects of pamidronate compared to standard care in patients with symptomatic ON (sON) and studied whether steroids might be continued after diagnosis of ON in some patients.

Short- and long-term outcome of patients with pseudo-vitamin D deficiency rickets treated with calcitriol.

BACKGROUND Pseudo-vitamin D deficiency rickets (PDDR; OMIM 264700) is a rare autosomal recessive disorder caused by mutations in the CYP27B1 gene, leading to an inability to synthesize 1α,25-dihydroxyvitamin D(3) (calcitriol). The long-term (>1 yr) effects of calcitriol replacement treatment have not been reported. MATERIALS AND METHODS Thirty-nine patients (20 females) with PDDR received calcitriol for periods of 2.0-26 yr. In 21 patients, data were available at diagnosis and during the first 2 yr of treatment with calcitriol. Twenty-five patients had reached their final height at the time of this analysis. RESULTS The most common presenting features were active rickets, neurological signs, and short stature. Treatment with calcitriol resulted in the normalization of biochemical parameters and mean lumbar spine areal bone mineral density z-scores within 3 months, whereas height z-scores increased more gradually. As to long-term effects, adult patients who had received calcitriol before the pubertal growth spurt (n = 11) had normal height, whereas patients who were treated with calcitriol only after puberty (n = 14) on average were short (height z-score -2.2). Lumbar spine areal bone mineral density z-scores were normal in all patients who had achieved final height. Nine women had 19 pregnancies, which all were without complications. All newborns were eucalcemic at birth. CONCLUSION Treatment with calcitriol started in infancy results in short- and long-term correction of all clinical, biochemical, and radiological abnormalities related to PDDR.