Primary hypomagnesemia

The clinical course of 2 patients with primary hypomagnesemia is reported. In one male patien, 5 months old, measurements of magnesium retention, intestinal absorption, fecal excretion and renal clearance were performed. The retention (2.8%) and absorption (7.8%) of 28-Mg were markedly reduced in comparison to controls (average retention 25% and average absorption 28%). The retention values of the parents and other relatives did not differ from those of healthy adults. The examined patient was successfully treated with trimagnesium dicitrate containing 1.75 g magnesium per day.     

Chronic hypomagnesemia and hypokalemia due to renal wasting in siblings

A 13 year old girl with carpopedal spasm is presented. Investigation values showed hypomagnesemia and hypokalemia. Her younger brother and sister demonstrated the same biochemical abnormalities without any symptoms. Their urinary excretion of magnesium and potassium were inappropriately high compared with their serum levels. Treatment with oral magnesium sulfate failed to correct the abnormalities, but serum levels of magnesium and potassium were just below the lower limits. This familial disease may represent congenital renal wasting of magnesium and potassium.     

Hyperekplexia in two siblings

Hyperekplexia is a rare, hereditary, non-epileptic disorder characterized by an exaggerated startle reaction to unexpected auditory, somatosensory and visual stimuli. The authors describe a one-day-old term neonate, who presented with jitteriness and episodic tonic spasms, and his elder sister with hyperekplexia. Hyperekplexia though is a rare disorder is one of the differential diagnoses for refractory tonic spasms in infancy. The prognosis is generally good in hereditary hyperekplexia. Recent molecular studies have revealed many associated mutations in the glycine receptor alpha and beta subunit genes.     

Baclofen overdose in two siblings

Baclofen is a muscle relaxant used in both adults and children with neuromuscular disorders to control spasticity. In children, relatively few cases of overdose have been previously reported. We report two cases of baclofen overdose occurring in two siblings. One sibling with cerebral palsy was being treated with baclofen at the time of overdose. Both cases presented with severe respiratory depression requiring mechanical ventilation. Serum baclofen concentrations from both children were significantly elevated. We also review the published literature on baclofen overdose in children and adolescents. These cases emphasize the importance of warning parents about the potential toxicity of baclofen when prescribing the drug to a family member.     

Marden-Walker syndrome in two siblings

Two siblings are reported who have features of the Marden-Walker syndrome. They have congenital joint contractures, camptodactyly, talipes equinovarus, abnormal facies, global delay in developmental milestones, hypotonia and failure to thrive. About 20 cases have been reported in the world literature. A summary of some of the cases is presented. This syndrome appears to be an autosomal recessive trait in some families.     

Primary familial hypomagnesemia syndrome: a new approach in treatment

Primary familial hypomagnesemia is a rare genetically determined disorder characterized by a selective defect in magnesium (Mg) absorption. Mutations of the transient receptor potential melastatin 6 (TRPM6) gene, which codes for TRPM6, the basic channel for intestinal Mg absorption and a new member of the transient receptor potential (TRP) family of cation channels, result in primary hypomagnesemia. Here we present a 14-year-old Turkish girl whose first symptoms manifested as neonatal tetany at 17 days old. During her follow-up, she was mainly taking high-dose oral Mg therapy. However, intravenous Mg and calcium (Ca) therapies were given during symptomatic attacks. When her requirements for Ca and Mg were increased during the pubertal growth period, which overlapped with increased loss of Mg during the summer, oral Ca and active vitamin D (calcitriol, Rocaltrol) were added. Calcitriol is needed because hypomagnesemia results in decreased production and resistance to the actions of active vitamin D, which leads to the disturbance of intracellular signal transmission. Although high-dose oral Mg is reported as a sufficient therapy in most of the patients with primary familial hypomagnesemia, addition of active vitamin D to the usual oral Mg and Ca therapy seems very useful, as in this patient.     

Infantile-onset megalencephalic leucoencephalopathy in two siblings

Infantile-onset megalencephalic leucoencephalopathy (IML) is a recently recognized autosomal recessive white matter disorder. Unlike other megalencephalic leucoencephalopathies, in patients with IML a mild clinical course, a slowly progressive delay in motor development and mild mental deterioration are typical. We report on two affected siblings who have typical clinical and radiological findings of IML. Cranial magnetic resonance imaging showed involvement of the capsula externa, extrema and interna, nucleus dentatus, crus cerebri, periventricular and subcortical white matter. In addition, bilateral cystic changes were determined predominantly in the temporal lobes. There were no clear biochemical or metabolic disturbances. In the present paper, we discuss the clinical and neuroimaging findings of IML.