遗传相关性低镁血症

镁离子在体内参与多种生化代谢反应,对各器官系统发挥正常生理功能起重要作用.体内镁离子的平衡主要依赖于肠道镁吸收和肾脏镁排泄的精密调节.遗传性低镁血症包括家族性低镁血症合并高尿钙和肾钙质沉着、常染色体显性遗传低镁血症合并低尿钙、家族性低镁血症继发低钙血症、常染色体显性遗传低钙血症等.近年来,对于这些遗传性低镁血症的基因研究及相关蛋白质功能研究使人们对体内镁离子转运机制有了更深一步的认识.     

家族性痉挛性截瘫七例及家族调查

本文报告7例家族性痉挛性截瘫的遗传方式来自3个不同的家族。家族(Ⅰ)三代中均为男性发病,连续两代出现,表现为常染色体显性、从性遗传,这是一种新的遗传方式,这种遗传方式目前尚未见报道。家族(Ⅱ)为常染色体显性遗传,家族(Ⅲ)为常染色体隐性遗传。     

遗传性肾小管性酸中毒4例报告

本文报道4例遗传性远曲管性肾小管酸中毒,均为女性,起病年龄30天～2岁。具有高氯性酸中毒,低血钾,尿pH>6.5及骨骼脱钙特点。临床表现为营养不良、肌无力、脱水和骨病等。本病系常染色体显性遗传,本组均有明显的家族成员患病史及遗传史。关于碱剂用量近年报道生长发育儿童须5～14mEq/kg/日(按HCO_2~-计算),能促进正常生长发育及防止肾钙化、肾结石。还强调低钾血症可导致低钾性心肌病而造成严重后果和针对低钾进行治疗的重要性。     

CLDN16 基因突变致家族性低镁血症高钙尿症与肾钙质沉着症1 例报告并文献复习

目的探讨家族性低镁血症高钙尿症和肾钙质沉着症(FHHNC)的临床特征和致病基因特点。方法分析1例2月龄FHHNC女性患儿的临床资料。结果患儿血镁低,尿钙高;肾脏超声提示肾髓质回声增强;多次尿培养大肠埃希菌。基因测序显示患儿CLDN16基因2处杂合变异c.324+1GC,c.317CT(p.Ser 106 Phe)。予抗感染及25%硫酸镁、门冬氨酸钾镁、10%枸橼酸钠口服治疗,病情好转。结论 FHHNC罕见且预后差,目前除肾移植外无特殊治疗方法,基因检测有助于早期诊断。     

35例不典型低镁血症的诊断和治疗探讨

通过对35例不典型低镁血症的临床分析,提示低镁血症并存于许多儿科疾病中,又常伴有其他电解质紊乱,及时正确的诊断常较困难,如能对血清镁测定作为感染性疾病的常规检查项目可避免误、漏诊.治疗应强调去除病因,给高镁饮食.仅有低血镁者可不必补镁,这种低血镁可随原发病的治愈而自行恢复.轻度低镁宜口服补镁,中、重度低镁者可肌注镁制剂,静脉滴注镁制剂应慎重。     

TRPM6基因变异致遗传性低镁血症1例报告并文献复习

目的分析遗传性低镁血症的诊断及治疗。方法回顾分析1例遗传性低镁血症患儿的临床资料,并复习文献。结果男性患儿,6月龄时因低镁血症导致抽搐就诊,补镁治疗后血镁仅能维持在0.6 mmol/L左右。全外显子测序显示患儿TRPM6存在复合杂合变异,c.2495AG(p.Tyr832Cys)和c.3357CA(p.Cys1119*)。患儿长期口服镁剂治疗,生长发育良好。结论 TRPM6基因c.2495AG和c.3357CA复合杂合变异可致遗传性低镁血症1型(肠型),及时诊断及治疗可避免不可逆的神经认知功能损害。     

新生儿颅内出血与低钙低镁血症

为了探讨新生儿颅内出血与低钙低镁血症的关系，本文作者对３６例新生儿颅内出血患者进行了血清钙、镁的检测。结果低血钙２２例，低镁６例，钙镁均低者５例。说明新和儿因可导致低钙低镁血症．     

家族性周期性麻痹8例报告和文献复习

目的报告8例儿童家族性周期性麻痹(FPP)病例,复习相关文献,以提高对其认识。方法回顾性总结8例FPP儿童的家系遗传特性、临床特征、辅助检查结果及治疗,分析其病因和诊断。结果6例为家族性低血钾型周期性麻痹,具有常染色体显性遗传的特征;发作时血清钾1.9~2.8 mmol/L,平均2.4 mmol/L;心电图出现U波等低血钾改变;其中1例血糖减低。另2例属于家族性正常血钾型周期性麻痹,也有常染色体显性遗传特性;发作时血清钾正常;1例血糖降低。8例甲状腺功能、肾功能和肌电图均正常。结论FPP为一组少见遗传性的骨髂肌离子通道病,根据家系遗传学特征、临床表现和相关辅助检查可确诊。     

小儿肺炎并呼衰`心衰时血钙,镁变化观察

呼吸衰竭常伴低钙血症,钙、镁制剂和强心甙合用比常规方法更能迅速平喘、改善心功能或控制某些常规方法无效的心衰。从而提示了肺炎并发呼衰、心衰的发生发展过程中,存在钙、镁代谢紊乱,为探讨这一问题,我们于1988年2～4月对30例支气管肺炎患儿进行血清总钙、镁、磷测定与补充钙、镁治疗,结果如下。     

家族性生长激素缺乏症的诊断思路

家族性生长激素缺乏症是由遗传基因变异引起的,可分为常染色体隐性遗传、常染色体显性遗传、X染色体隐性遗传等模式。仔细采集病史、明确临床表型、合理应用分子生物学方法进行基因学诊断是明确遗传类型及找到相关突变基因的关键。     

先天性肥厚性幽门狭窄围手术期低钙低镁血症

３２例肥厚性幽门狭窄患儿，因长期大量呕吐、摄入不足及吸收障碍等原因，均有不同程度的低钙、低镁血症，其中低钙２４例，低镁１８例，钙、镁均低者１６例。临床表现为易惊、睡眠不安、夜哭、四肢震颤、头向后仰、背肌紧张、面部抽搐，严重者出现喉痉挛。经使用钙、镁制剂后得到控制。     

Primary idiopathic hypomagnesemia in two female siblings

Two female siblings with primary idiopathic hypomagnesemia, born to consanguineous parents, are described. Both presented at 6 weeks of age, with convulsions and persistent hypocalcemia (calcium 1.5 and 1.6 mmol/1; normal range (NR) 2.2-2.6 mmol/1), which could not be controlled with anticonvulsants and/or calcium gluconate. On further investigation they were also found to have hypomagnesemia (magnesium 0.17 mmol/1 and 0.22 mmol/l; NR 0.65-1.05 mmol/l). Convulsions and the low serum calcium and magnesium levels were first managed by im and then by oral administration of magnesium supplements. A burst in circulating parathyroid hormone levels to well above the physiological range was observed at the start of therapy. Serum magnesium values of the mother and father were just below the normal range, with normal serum calcium. This type of infantile primary hypomagnesemia appears to be a hereditary disease with autosomal recessive characteristics, although a partially penetrant X-linked or autosomal dominant trait cannot be excluded.
Convulsions,primary hypomagnesemia     

Autosomal dominant hypoparathyroidism with severe hypomagnesemia and hypocalcemia, successfully treated with recombinant PTH and continuous subcutaneous magnesium infusion

Activating calcium sensor receptor (CaSR) mutations often present with hypocalcemia and hypomagnesemia. Severe hypocalcemia with this mutation has been reported but severe hypomagnesemia has not been well described. AIM: To identify the cause of severe hypocalcemia and hypomagnesemia in a young child, and explore the efficacy of continuous subcutaneous magnesium therapy as a safer alternative to intravenous magnesium. PATIENT: A 2-8/12 year-old female with severe hypocalcemia and hypomagnesemia of unknown etiology. METHODS: Genetic analysis was performed on the proband and both parents. The proband was treated with human parathyroid hormone (teriparatide) and a continuous infusion of subcutaneous magnesium sulfate initially using a Deltec insulin pump and subsequently a Curlin infusion pump. RESULTS: The patient has a known de novo mutation in the CASR gene (A843E). She could not be adequately managed with enteral and intravenous electrolyte replacement even after adding teriparatide. She responded well to adjunctive therapy with continuous subcutaneous magnesium. CONCLUSIONS: Severe hypomagnesemia can be part of the phenotype of activating CaSR mutations. Subcutaneous magnesium should be considered in patients with difficult to control hypomagnesemia.     

Polycythemia, hypomagnesemia, and hypocalcemia in infants of diabetic mothers

Hypomagnesemia (serum magnesium concentration, less than 1.5 mg/dL [0.62 mmol/L]) and hypocalcemia (serum calcium concentration, less than 8 mg/dL [2.00 mmol/L]) have been reported in polycythemic infants, as well as in infants of diabetic mothers (IDMs). These latter infants are at risk for neonatal polycythemia (venous hematocrit, greater than or equal to 65% [0.65]). We tested the hypothesis that neonatal polycythemia in IDMs is associated with increased serum calcitonin concentration, hypomagnesemia, and hypocalcemia. Serum magnesium and calcium concentrations were measured at 24 and 72 hours of age in 76 IDMs; serum calcitonin concentration was measured at 24 hours of age. Peripheral venous spun hematocrit was measured between 2 and 4 hours of age. The rates of hypomagnesemia and hypocalcemia were similar in polycythemic and nonpolycythemic IDMs (0% vs 9% and 56% vs 49%, respectively). The serum calcitonin concentration was similar in both groups. There was no correlation between hematocrit and the serum magnesium or calcium concentration; a significant association existed between hypocalcemia and hypomagnesemia.     

Severe renal osteodystrophy without elevated serum immunoreactive parathyroid hormone concentrations in hypomagnesemia due to renal magnesium wasting

An 8 1/2-year-old girl presented with a long history of seizures, growth retardation, muscle weakness, gait disturbance, and hearing loss. Her evaluation revealed chronic moderate renal failure (serum creatinine 2.2 mg/dL), severe hypocalcemia (5 mg/dL), hyperphosphatemia (8.1 mg/dL), hypomagnesemia (1.5 mg/dL), increased urinary magnesium excretion (2 mg/kg/d), high fractional excretion of magnesium (21.7%), hypokalemia (3.2 mEq/L), and hyperkaliuria (26 mEq/L). Low circulating immunoreactive parathyroid hormone levels for the degree of the hypocalcemia (serum N-parathyroid hormone 212 pg/mL) and severe rickets without evidence of osteitis fibrosa cystica were found. The patient probably has primary renal leak hypomagnesemia (magnesuric hypomagnesemia) which caused impaired secretion of immunoreactive parathyroid hormone leading to severe hypocalcemia and calcium deficiency rickets. Treatment with magnesium and calcium supplements, calcitriol, and aluminum hydroxide resulted in marked clinical, biochemical, and radiologic improvement. Calcium deficiency rickets due to primary or secondary renal magnesium wasting in conjunction with moderate renal failure represents a largely unrecognized metabolic bone disease.     

Myocardial dysfunction due to hypocalcemia

Hypocalcemia is a curable cause of myocardial dysfunction and clinical congestive cardiac failure, with only stray reports available in literature. We describe 15 infants presenting with severe left ventricular dysfunction, who were found to have hypocalcemia with or without hypomagnesemia. Vitamin D deficiency was identified as the main cause of hypocalcemia. These children improved on supplementation of vitamin D and calcium.     

The etiology of enamel hypoplasia: a unifying concept

In a study of children with chronic disorders of calcium and phosphate homeostasis, enamel hypoplasia was found in hereditary vitamin D-dependency rickets and in hypoparathyroidism, conditions characterized by hypocalcemia, and was not found in X-linked hypophosphatemic rickets, a condition in which the plasma calcium concentration is normal. The occurrence of enamel hypoplasia bore no relation to the plasma phosphate concentration. Enamel hypoplasia has also been reported in other pediatric disorders in which hypocalcemia is a major sign (for example, vitamin D deficiency, prematurity, and neonatal tetany). The existence of enamel hypoplasia in a hypoparathyroid or rachitic patient, when correlated with the chronology of enamel mineralization, helps to establish the time of onset of hypocalcemia. The observations led us to the hypothesis that a low serum calcium concentration during enamel formation is a specific determinant of enamel hypoplasia. This hypothesis may be relevant to the etiology of linear enamel hypoplasia, an endemic lesion of primary teeth in children of many Third World countries that predisposes the teeth to dental caries. The hypothesis may therefore be relevant also in explaining the prevalence of caries in the primary teeth of children in many underdeveloped countries.     

Prevalence of Hypocalcemia in Seizures in Infancy

A one-year prospective study on developmentally normal children between 1-mo to 2-y with seizures was done to study the prevalence of hypocalcemia. The contribution of hypovitaminosis-D to hypocalcemia was also studied. Of 78 infants (51 boys) enrolled, 18 (23.1%) had hypocalcemia. Fifteen (19.2%) had hypocalcemia secondary to hypovitaminosis-D and 3 (3.8%) had hypomagnesemia. In infants aged less than 6 mo who were exclusively breastfed, 15 (41.67%) had hypocalcemia in comparison to other two age groups [2 (10.53%) in 6–12 mo age-group and 1 (4.35%) in 1–2 y age-group]. This association was statistically significant (p?=?0.001).     

Transient neutral fat steatorrhea, elevated sweat chloride concentration, and hypoparathyroidism in a child with celiac disease

A patient with celiac disease and the unusual features of transiently elevated sweat chlorides, reversible exocrine pancreatic insufficiency, symptomatic hypocalcemia/hypomagnesemia, and transient secondary hypoparathyroidism is presented along with a brief discussion of the physiologic mechanisms thought to underlie their development.