Variación estacional de 25-hidroxi-vitamina D3, hormona paratiroidea y fosfatasa alcalina en niños escolares / Seasonal variations in 25-hydroxy vitamin D3, parathormone and alkaline phosphatase in school-aged children

INTRODUCCIÓN: El principal rol de la vitamina D es la regulación del metabolismo del calcio, cuya principal fuen te es la vitamina D3 que se obtiene principalmente por la acción de la luz ultravioleta (UV) en la piel. OBJETIVO: Evaluar las diferencias estacionales en las concentraciones de 25-hidroxi-vitamina D3 (25OHVitD3), hormona paratiroidea (PTH), fosfatasa alcalina (FA) y calcio en niños en edad esco lar. SUJETOS Y MÉTODO: Se midieron las concentraciones de 25OHVitD3, PTH, FA y calcio en niños de 5 a 8 años, sin suplementación de Vitamina D, reclutados en Santiago de Chile (latitud -33.4372) en distintas estaciones del año. El estatus de VitD fue definido como suficiente con concentraciones de 25OHVitD3 > 20 ng/mL (50 nmol/L), insuficiente 12-20 ng/mL (30-50 nmol/L) y deficiente 20 ng/mL) en verano, lo que disminuyó significativamente en invierno (54,3%, p < 0,0001). CONCLUSIONES: Las concentraciones de 25OHVitD3 disminuyeron en aproximadamente la mitad de los niños durante el invierno, lo que se vio acompañado de un aumento de la PTH y FA, asociado a concentraciones normales de calcio. De acuerdo a nuestros resultados, la suplementación con VitD en niños podría ser necesaria durante otoño e invierno.

INTRODUCTION: The main role of Vitamin D is to regulate calcium metabolism, whose main source is vitamin D3 ob tained mostly from the action of ultraviolet (UV) light on the skin. OBJECTIVE: To evaluate the seaso nal differences in the concentrations of 25-hydroxy-vitamin D3 (25OHVitD3), parathyroid hormone (PTH), alkaline phosphatase (ALP), and calcium in school-age children. SUBJECTS AND METHOD: The concentrations of 25OHVitD3, PTH, ALP, and calcium were measured in children from Santiago, Chile (latitude -33.4372), aged 5 to 8 years, without Vitamin D supplementation, in different seasons of the year. VitD status was defined as sufficient with concentrations of 25OHVitD3 >20 ng/mL (50 nmol/L), insufficient 12-20 ng/mL (30-50 nmol/L) and deficient 20 ng/mL), which decreased significantly in winter to 54.3% (p <0.0001). CONCLUSIONS: In winter, 25OHVitD3 concentrations decreased in approximately half of the children, which was associated with an increase in PTH and ALP, and normal calcium concentrations. According to our results, children may need VitD supple mentation during fall and winter.

[Seasonal variations in 25-hydroxy vitamin D3, parathormone and alkaline phosphatase in school-aged children]. / Variación estacional de 25-hidroxi-vitamina D3, hormona paratiroidea y fosfatasa alcalina en niños escolares.

INTRODUCTION: The main role of Vitamin D is to regulate calcium metabolism, whose main source is vitamin D3 ob tained mostly from the action of ultraviolet (UV) light on the skin. OBJECTIVE: To evaluate the seaso nal differences in the concentrations of 25-hydroxy-vitamin D3 (25OHVitD3), parathyroid hormone (PTH), alkaline phosphatase (ALP), and calcium in school-age children. SUBJECTS AND METHOD: The concentrations of 25OHVitD3, PTH, ALP, and calcium were measured in children from Santiago, Chile (latitude -33.4372), aged 5 to 8 years, without Vitamin D supplementation, in different seasons of the year. VitD status was defined as sufficient with concentrations of 25OHVitD3 >20 ng/mL (50 nmol/L), insufficient 12-20 ng/mL (30-50 nmol/L) and deficient <12 ng/mL (30 nmol/L) based on the recommendations of the expert group of the "Global Consensus for the Prevention and Mana gement of Nutritional Rickets". RESULTS: 133 children participated (89 preterms under or equal to 32 weeks), 41 during summer, 28 in fall, 35 in winter, and 29 in spring. The difference of means between summer and winter was 9.6 ng/mL for 25OHVitD3 (p <0.0001), -11.1 pg/mL for PTH (p <0.0001), and -47.5 IU/mL for ALP (p= 0.01). There were no differences in calcium concentrations. In sum mer, 97.6% of the subjects were classified with sufficiency status (> 20 ng/mL), which decreased significantly in winter to 54.3% (p <0.0001). CONCLUSIONS: In winter, 25OHVitD3 concentrations decreased in approximately half of the children, which was associated with an increase in PTH and ALP, and normal calcium concentrations. According to our results, children may need VitD supple mentation during fall and winter.

Urinary sodium-to-potassium ratio and plasma renin and aldosterone concentrations in normotensive children: implications for the interpretation of results.

OBJECTIVES: To identify associations among the plasma renin concentration (PRC), plasma aldosterone and urinary sodium (Na)/potassium (K) ratio, and to integrate these variables into a nomogram with the aim of estimating the expected versus observed aldosterone concentration. METHODS: We studied 40 healthy normotensive children (5-8 years old, 57.5% girls) who were born at term and were adequate for their gestational age. Following overnight fasting, the PRC and plasma aldosterone in blood samples were measured, and the Na/K ratio was calculated from a simultaneously obtained urinary spot sample. A mathematical function was defined with these three variables, and a nomogram was built that would return the expected aldosterone concentration from the obtained plasma renin and urinary Na/K ratio values. RESULTS: The PRC (B =  5.9, P < 0.001) and urinary Na/K ratio (B = -98.1, P = 0.003) were significant independent predictors of plasma aldosterone. The correlation between the observed plasma aldosterone and the expected plasma aldosterone, as obtained from the nomogram, was r = 0.88, P < 0.001. The average difference between the observed and expected plasma aldosterone was -0.89, with a standard deviation of ±30%. CONCLUSION: The strong correlation between the urinary Na/K ratio, from urine samples taken at the same as the blood samples, and plasma renin and aldosterone concentrations allowed us to build a nomogram to predict aldosterone levels. This approach may be useful for evaluating the renin-angiotensin-aldosterone system (RAAS) in pediatric patients with hypertension and RAAS dysfunction.

Mutations in MAGEL2 and L1CAM Are Associated With Congenital Hypopituitarism and Arthrogryposis.

CONTEXT: Congenital hypopituitarism (CH) is rarely observed in combination with severe joint contractures (arthrogryposis). Schaaf-Yang syndrome (SHFYNG) phenotypically overlaps with Prader-Willi syndrome, with patients also manifesting arthrogryposis. L1 syndrome, a group of X-linked disorders that include hydrocephalus and lower limb spasticity, also rarely presents with arthrogryposis. OBJECTIVE: We investigated the molecular basis underlying the combination of CH and arthrogryposis in five patients. PATIENTS: The heterozygous p.Q666fs*47 mutation in the maternally imprinted MAGEL2 gene, previously described in multiple patients with SHFYNG, was identified in patients 1 to 4, all of whom manifested growth hormone deficiency and variable SHFYNG features, including dysmorphism, developmental delay, sleep apnea, and visual problems. Nonidentical twins (patients 2 and 3) had diabetes insipidus and macrocephaly, and patient 4 presented with ACTH insufficiency. The hemizygous L1CAM variant p.G452R, previously implicated in patients with L1 syndrome, was identified in patient 5, who presented with antenatal hydrocephalus. RESULTS: Human embryonic expression analysis revealed MAGEL2 transcripts in the developing hypothalamus and ventral diencephalon at Carnegie stages (CSs) 19, 20, and 23 and in the Rathke pouch at CS20 and CS23. L1CAM was expressed in the developing hypothalamus, ventral diencephalon, and hindbrain (CS19, CS20, CS23), but not in the Rathke pouch. CONCLUSION: We report MAGEL2 and L1CAM mutations in four pedigrees with variable CH and arthrogryposis. Patients presenting early in life with this combined phenotype should be examined for features of SHFYNG and/or L1 syndrome. This study highlights the association of hypothalamo-pituitary disease with MAGEL2 and L1CAM mutations.

ALS deficiency caused by an exon 2 deletion and a novel missense variant in the gene encoding ALS.

CONTEXT: ALS deficiency (ACLSD), caused by mutations in IGFALS, is characterized by a mild short stature, low concentrations of IGF-I and IGFBP-3, and a normal growth hormone (GH) stimulation test response. To our knowledge, no larger deletions have been reported. CASE DESCRIPTION: A 17-year-old adolescent male was evaluated due to delayed puberty and short stature. He had a height of 154.4 cm (SDS -2.84), a weight of 53.3 kg (SDS -1.41), a BMI of 22.4 kg/m2 (SDS +0.31), a Tanner 2 pubertal stage with a testicular volume of 10 mL, and a bone age of 16 years (SDS -1.33). After biochemical evaluation, low IGF-I levels, undetectable IGFBP-3 levels, and a normal response to the GH stimulation test were observed, suggesting GH insensitivity. ACLSD was confirmed by ALS measurement (116 ng/mL, SDS -3.19) and genetic analysis of IGFALS. An apparently homozygous missense variant, p. Pro624Leu, was found in exon 2 of the proband; this mutation was observed on one allele of the proband's father but was absent in the mother and siblings. Deletion/duplication analysis by multiplex ligation-dependent probe amplification (MLPA) was consistent with a deletion encompassing a significant part of exon 2 on one allele in the proband and in his mother and siblings. CONCLUSION: This is the first report of a large deletion in a patient with ACLSD. Deletion/duplication analysis should be considered in the genetic study of ACLSD, especially when homozygosity for a pathogenic variant cannot be confirmed by the study of the parents or when no variants are found but ALS concentrations are very low.

Tumor ovárico de células de Leydig en una niña de 7 años que se presentó como pubarquia precoz con elevación de 17 hidroxiprogesterona / Ovarian tumor of Leydig cells in a 7-year-old girl who presented as precocious pubarche with elevation of 17 hydroxyprogesterone

Clinical case: a girl of 7 ½ years who consulted for early pubarche without thelark, with a percentile size of 75 for a genetic target size in the 10th percentile, overweight with a 90th percentile BMI, and normal blood pressure. The biochemical study showed high levels of androgens: testosterone: 7.2 ng/dL, androstenedione of 5.1 ng / ml, 17OHP: 15 ng / dL with low normal DHEAS (0.26 ug/ml), Plasma Renin Activity normal low: 0.22 ng/mL/h. Initial imaging study showed a bone age of 10 years 6 months and normal abdominal and pelvic ultrasound. Molecular study showed no pathogenic variants in the CYP21A2 gene (21 Hydroxylase). With a probable diagnosis of non-classical congenital adrenal hyperplasia (HSRNC) and no known mutation, he started treatment with hydrocortisone (12 mg/m2). At 8.7 years, pubertal development begins and braking begins with LHRH analogues, which are administered for 18 months. Despite the treatment, signs of virilization and elevation of androgens (testosterone up to 130 ng/ml) are progressively accentuated, which do not diminish when trying different corticosteroid schemes. MRI of the abdomen and pelvis shows the normal adrenal glands and a solid nodular image of 2.1 x 1.6 cm in the right ovary (Figure 2), later demonstrated with pelvic ultrasound (Figure 2). Right laparoscopic oophorectomy was performed, whose biopsy demonstrated a Leydig cell tumor. One month after surgery, all androgenic levels were normalized, so the gradual suspension of corticosteroids began. Conclusion: Although HSRNC is the most frequent pathological cause of early pubarche, when it is associated with progressive clinical and biochemical hyperandrogenism despite adequate treatment and without pathogenic variants in the CYP21A2 gene, even with high levels of 17OHP, other causes should be considered, specifically, androgen producing tumors.

Caso clínico: niña de 7½ años que consulta por pubarquia precoz sin telarquia, con talla en percentil 75 para una talla objetivo genético en percentil 10, sobrepeso con IMC percentil 90 y presión arterial normal. El estudio bioquímico mostró niveles elevados de andrógenos: testosterona: 7,2 ng/dL, androstenediona de 5,1 ng/ml, 17OHP: 15 ng/dL con DHEAS normal baja (0,26 ug/ml), Actividad de Renina Plasmática normal baja: 0.22 ng/ mL/h. Estudio de imágenes inicial mostró una edad ósea de 10 años 6 meses y ecografía abdominal y pelviana normales. Estudio molecular no mostró variantes patogénicas en el gen CYP21A2 (21 Hidroxilasa). Con diagnosticó probable de hiperplasia suprarrenal congénita no clásica (HSRNC) y sin mutación conocida,inició el tratamiento con hidrocortisona (12 mg/m2). A los 8.7 años comienza desarrollo puberal y se inicia frenación con análogos de LHRH, los cuales se administran por 18 meses. A pesar del tratamiento se acentúan progresivamente los signos de virilización y hayelevación de los andrógenos (testosterona hasta 130 ng/ml), que no disminuyen intentando diferentes esquemas de corticoides. Se realiza RM de abdomen y pelvis que muestra las glándulas suprarrenales normales y una imagen nodular sólida de 2.1 x 1.6 cm en el ovario derecho (Figura 2), demostrada posteriormente con Ecografía pelviana (Figura 2). Se realiza ooforectomía derecha por vía laparoscópica, cuya biopsia demostró un tumor de células de Leydig. Un mes después de la cirugía, se normalizan todos los niveles androgénicos por lo que se inició la suspensión gradual de los corticoides. Conclusión: Aunque la HSRNC es la causa patológica más frecuente de la pubarquia precoz, cuando se asocia con un hiperandrogenismo clínico y bioquímico progresivo a pesar de un tratamiento adecuado y sin variantes patógenicas en el gen CYP21A2, incluso con niveles elevados de 17OHP, otras causas deben ser consideradas, específicamente tumores productores de andrógenos.