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1.
J Neurol Sci ; 400: 47-51, 2019 May 15.
Article in English | MEDLINE | ID: mdl-30903859

ABSTRACT

Copper deficiency (hypocupremia) or toxicosis (hypercupremia) may cause disorders of central and peripheral nervous systems. Hypocupremia causes myeloneuropathy resembling vitamin B12 deficiency. However, the clinical manifestations, particularly peripheral neuropathy (PN), of hypercupremia have not been adequately evaluated. To compare clinical, laboratory and electrodiagnositc features of PN between patients with hypocupremia and hypercupremia, we retrospectively reviewed the charts of patients with abnormal copper levels. Subjects with zinc abnormalities were excluded. Five hypocupremia (Male/Female = 4/1; age: 54.6 ±â€¯17.1 years; copper = 55.0 ±â€¯8.5 µg/dL [normal = 72-175]; zinc = 74.4 ±â€¯15.5 µg/dL [normal = 60-130]) and 3 hypercupremia (M/F = 1/2; age: 57.0 ±â€¯8.2 years; copper = 215.0 ±â€¯10.8 µg/dL; zinc = 72.3 ±â€¯14.6 µg/dL) were studied. The notable clinical findings included ambulatory difficulty in hypocupremia (2/5); paresthesia in both hypocupremia (3/5) and hypercupremia (2/3) but pain was only seen in (3/3) hypercupremia patients. Tendon reflexes were decreased in hypocupremia (3/5) and hypercupremia (1/3) but hyperreflexias in hypocupremia (2/5) only. Preexisting comorbidity such as diarrhea were observed in (2/3) hypercupremia but not in hypocupremia patients. Laboratory findings showed vitamin D deficiency (16.4 ±â€¯5.6 ng/mL) in (2/2) hypercupremia but normal (40.4 ±â€¯4.7 ng/mL) in (2/2) hypocupremia. Neurophysiologic studies showed evidence of neuropathy in (3/5) hypocupremia only. Different patterns of clinical, neurological examination and electrophysiologic findings between hypocupremia and hypercupremia suggest different underlying pathophysiologies.


Subject(s)
Copper/blood , Copper/deficiency , Copper/toxicity , Electrodiagnosis/methods , Liver Cirrhosis/blood , Metal Metabolism, Inborn Errors/blood , Peripheral Nervous System Diseases/blood , Adult , Aged , Female , Humans , Liver Cirrhosis/diagnosis , Liver Cirrhosis/physiopathology , Male , Metal Metabolism, Inborn Errors/diagnosis , Metal Metabolism, Inborn Errors/physiopathology , Middle Aged , Peripheral Nervous System Diseases/diagnosis , Peripheral Nervous System Diseases/physiopathology , Retrospective Studies
2.
Pediatr Blood Cancer ; 65(2)2018 Feb.
Article in English | MEDLINE | ID: mdl-28895280

ABSTRACT

Congenital hypotransferrinemia (OMIM 209300) is an extremely rare disorder of inherited iron metabolism. Since its description in 1961, only 16 cases have been reported. The defective gene and molecular defect causing this disorder and clinicolaboratory findings seen in the homozygous and heterozygous states have been documented in both humans and mice. However, due to the lack of follow-up studies of the described cases, the long-term prognosis remains unknown. We present a 10-year observational follow-up of a patient previously diagnosed on a molecular basis who was treated with a unique therapy of plasma transfusion fortified with oral iron, with satisfactory clinicolaboratory responses.


Subject(s)
Blood Component Transfusion , Child Development , Iron/administration & dosage , Metal Metabolism, Inborn Errors/blood , Metal Metabolism, Inborn Errors/therapy , Plasma , Transferrin/deficiency , Administration, Oral , Child , Female , Follow-Up Studies , Humans
3.
Clin Exp Rheumatol ; 35 Suppl 108(6): 113-115, 2017.
Article in English | MEDLINE | ID: mdl-28628471

ABSTRACT

OBJECTIVES: Hyperzincaemia/hypercalprotectinemia (Hz/Hc) syndrome is a recently described condition caused by a specific de novo mutation (E250K) affecting PSTPIP1 gene. It has a phenotype distinct from classical pyogenic arthritis, pyoderma gangrenosum, and acne (PAPA) syndrome that includes severe systemic and cutaneous inflammation, hepatosplenomegaly, arthritis without sequelae, pancytopenia and failure to thrive. METHODS: We describe an 8-year-old boy who presented recurrent right knee swelling mimicking septic arthritis and persistent bone marrow involvement, without cutaneous involvement. RESULTS: Molecular analysis of the PSTPIP1 gene revealed the presence of a heterozygous E250K mutation. No growth failure was detected nor in the patient neither in his mother, carrying the same variant. Blood zinc and calprotectin MRP8/14 concentrations of the patient were found to be markedly increased. Therapy with anakinra was started with rapid disappearance of clinical symptoms and normalization of CRP levels in 24 hours, but persistence of bone marrow involvement. CONCLUSIONS: The patient described has a milder phenotype, with no skin features, minor episodes of arthritis with no sequelae and normal growth. Compared to the patients with de novo mutations described in the literature, familial cases seem to have a milder phenotype. Our case further confirms the lack of efficacy of anakinra on bone marrow involvement.


Subject(s)
Acne Vulgaris/genetics , Adaptor Proteins, Signal Transducing/genetics , Arthritis, Infectious/genetics , Cytoskeletal Proteins/genetics , Metal Metabolism, Inborn Errors/genetics , Mutation/genetics , Pyoderma Gangrenosum/genetics , ATP-Binding Cassette Transporters/blood , Acne Vulgaris/blood , Acne Vulgaris/diagnosis , Acne Vulgaris/drug therapy , Antirheumatic Agents/therapeutic use , Arthritis, Infectious/blood , Arthritis, Infectious/diagnosis , Arthritis, Infectious/drug therapy , Biomarkers/blood , C-Reactive Protein/metabolism , Calgranulin B/blood , Child , DNA Mutational Analysis , Genetic Predisposition to Disease , Heterozygote , Humans , Interleukin 1 Receptor Antagonist Protein/therapeutic use , Male , Metal Metabolism, Inborn Errors/blood , Metal Metabolism, Inborn Errors/diagnosis , Metal Metabolism, Inborn Errors/drug therapy , Phenotype , Predictive Value of Tests , Pyoderma Gangrenosum/blood , Pyoderma Gangrenosum/diagnosis , Pyoderma Gangrenosum/drug therapy , Risk Factors , Treatment Outcome , Zinc/blood
4.
Hum Genet ; 135(7): 813-26, 2016 07.
Article in English | MEDLINE | ID: mdl-27138983

ABSTRACT

Molybdenum cofactor (MoCo) deficiency is a rare, autosomal-recessive disorder, mainly caused by mutations in MOCS1 (MoCo deficiency type A) or MOCS2 (MoCo deficiency type B) genes; the absence of active MoCo results in a deficiency in all MoCo-dependent enzymes. Patients with MoCo deficiency present with neonatal seizures, feeding difficulties, severe developmental delay, brain atrophy and early childhood death. Although substitution therapy with cyclic pyranopterin monophosphate (cPMP) has been successfully used in both Mocs1 knockout mice and in patients with MoCo deficiency type A, there is currently no Mocs2 knockout mouse and no curative therapy for patients with MoCo deficiency type B. Therefore, we generated and characterized a Mocs2-null mouse model of MoCo deficiency type B. Expression analyses of Mocs2 revealed a ubiquitous expression pattern; however, at the cellular level, specific cells show prominent Mocs2 expression, e.g., neuronal cells in cortex, hippocampus and brainstem. Phenotypic analyses demonstrated that Mocs2 knockout mice failed to thrive and died within 11 days after birth. None of the tested MoCo-dependent enzymes were active in Mocs2-deficient mice, leading to elevated concentrations of purines, such as hypoxanthine and xanthine, and non-detectable levels of uric acid in the serum and urine. Moreover, elevated concentrations of S-sulfocysteine were measured in the serum and urine. Increased levels of xanthine resulted in bladder and kidney stone formation, whereas increased concentrations of toxic sulfite triggered neuronal apoptosis. In conclusion, Mocs2-deficient mice recapitulate the severe phenotype observed in humans and can now serve as a model for preclinical therapeutic approaches for MoCo deficiency type B.


Subject(s)
Coenzymes/genetics , Metal Metabolism, Inborn Errors/genetics , Metalloproteins/genetics , Nuclear Proteins/genetics , Animals , Apoptosis/genetics , Carbon-Carbon Lyases , Coenzymes/biosynthesis , Cysteine/analogs & derivatives , Cysteine/urine , Disease Models, Animal , Gene Expression , Humans , Hypoxanthine/blood , Hypoxanthine/urine , Metal Metabolism, Inborn Errors/blood , Metal Metabolism, Inborn Errors/physiopathology , Metal Metabolism, Inborn Errors/urine , Metalloproteins/biosynthesis , Mice , Mice, Knockout , Molybdenum Cofactors , Mutation , Nuclear Proteins/biosynthesis , Phenotype , Pteridines , Xanthine/blood , Xanthine/urine
5.
Mov Disord ; 30(7): 996-1001, 2015 Jun.
Article in English | MEDLINE | ID: mdl-25778823

ABSTRACT

BACKGROUND: SLC30A10 mutations cause an autosomal recessive disorder, characterized by hypermanganesaemia, polycythemia, early-onset dystonia, paraparesis, or late-onset parkinsonism, and chronic liver disease. This is the first identified inborn error of Mn metabolism in humans, reported in 10 families thus far. METHODS: Methods for this study consisted of clinical examination, neuroimaging studies (MRI), serum dosages, and SLC30A10 genetic analysis. RESULTS: We describe early disease manifestations (including videos) in 5 previously unreported Indian children, carrying novel homozygous SLC30A10 mutations. Gait and speech disturbances, falls, dystonias, and central hypotonia were the presenting neurological features, starting within the first 5 years of life. All children also had severe hypermanganesemia, polycythemia, variable degree of liver disease, and marked brain MRI T1 hyperintensities. CONCLUSIONS: Our findings expand the mutational and clinical spectra of this recently recognized disorder. An early diagnosis is warranted, because treatment with manganese-chelating agents, iron supplementation, or their combination might improve symptoms and prevent progression of this otherwise potentially fatal disease. © 2015 International Parkinson and Movement Disorder Society.


Subject(s)
Cation Transport Proteins/genetics , Dystonia/genetics , Dystonia/physiopathology , Manganese/metabolism , Metal Metabolism, Inborn Errors/genetics , Metal Metabolism, Inborn Errors/physiopathology , Adolescent , Child, Preschool , Consanguinity , Dystonia/blood , Dystonia/etiology , Female , Humans , Male , Metal Metabolism, Inborn Errors/blood , Metal Metabolism, Inborn Errors/complications , Mutation , Pedigree , Phenotype , Zinc Transporter 8
6.
Blood Cells Mol Dis ; 54(2): 151-4, 2015 Feb.
Article in English | MEDLINE | ID: mdl-25486930

ABSTRACT

As our understanding of iron metabolism improves through the more accurate description of iron metabolism actors, new causes of iron overload are identified. We, here, report 16 cases of hereditary hypotransferrinemia related to 4 previously undescribed TF (transferrin) mutations (p.Val221Gly, p.Arg609Trp, p.Glu370Lys, p.Tyr533X and p.Cys421Arg). We show that, besides increasing serum transferrin saturation without iron overload, hypotransferrinemia, when associated to mutations in HFE or HAMP or to acquired factors, can lead to clinically relevant iron burden. These cases emphasize the usefulness of serum transferrin determination in the diagnostic evaluation of iron overload and the importance for clinicians to be aware of this syndrome.


Subject(s)
Hepcidins/genetics , Histocompatibility Antigens Class I/genetics , Iron Overload/genetics , Iron/metabolism , Membrane Proteins/genetics , Metal Metabolism, Inborn Errors/genetics , Mutation , Transferrin/deficiency , Transferrin/genetics , Adult , Aged , DNA Mutational Analysis , Female , Gene Expression , Genotype , Hemochromatosis Protein , Hepcidins/metabolism , Heterozygote , Histocompatibility Antigens Class I/metabolism , Humans , Iron Overload/blood , Iron Overload/etiology , Iron Overload/pathology , Male , Membrane Proteins/metabolism , Metal Metabolism, Inborn Errors/blood , Metal Metabolism, Inborn Errors/complications , Metal Metabolism, Inborn Errors/pathology , Middle Aged , Pedigree , Transferrin/metabolism
7.
Nephrol Dial Transplant ; 29 Suppl 4: iv63-71, 2014 Sep.
Article in English | MEDLINE | ID: mdl-25165187

ABSTRACT

The kidney plays a key role in the maintenance of normal magnesium balance. The distal tubule of the kidney, namely the thick ascending limb of the loop of Henle and the distal convoluted tubule, is crucial for the regulation of serum magnesium levels and body magnesium content. The identification of molecular defects related to rare inherited magnesium losing disorders has contributed greatly to a better understanding of the process of renal magnesium handling. Since the number of genetic defects related to magnesium metabolism is still increasing, it might be expected that our knowledge on magnesium physiology will further improve. This knowledge will hopefully lead to therapeutic strategies that enable specific therapies for patients suffering from the symptoms and possible sequelae of chronic magnesium depletion.


Subject(s)
Hypercalciuria/genetics , Magnesium Deficiency/genetics , Magnesium/blood , Metal Metabolism, Inborn Errors/genetics , Nephrocalcinosis/genetics , Renal Tubular Transport, Inborn Errors/genetics , Humans , Magnesium Deficiency/blood , Metal Metabolism, Inborn Errors/blood
8.
Neonatology ; 103(1): 54-9, 2013.
Article in English | MEDLINE | ID: mdl-23128541

ABSTRACT

BACKGROUND: Low birth weight (LBW) infants are at high risk of zinc deficiency, but there is a paucity of data on their zinc status. OBJECTIVE: To evaluate zinc status of LBW (BW <2,500 g) and normal birth weight (NBW; BW ≥ 2,500 g) infants at birth and in early infancy. METHODS: A total of 339 infants (LBW, n = 220; NBW, n = 119) were enrolled, and venous blood samples of mother-infant dyad were taken within 48 h of birth. Infants' levels were repeated between 2 and 10 months of age. Serum zinc levels were estimated using an inductively coupled plasma mass spectrometer. Primary outcome was zinc deficiency, defined as serum zinc <65 µg/dl. RESULTS: Zinc results were available for 182 LBW and 103 NBW infants at birth and for 100 LBW and 66 NBW infants at follow-up with a median postnatal age of 14 and 15.5 weeks, respectively. Median zinc levels were low and comparable at birth as well as at follow-up, with zinc deficiency being present in 51.0% of LBW and 42.4% of NBW infants at birth and in 79.0% of LBW and 66.7% of NBW infants at follow-up. Zinc levels decreased significantly in both groups from birth to follow-up, irrespective of zinc multivitamin supplementation. Zinc levels of infants with BW <2,000 g at follow-up were significantly lower compared to infants with higher BW. CONCLUSION: Zinc status was poor in many infants at birth irrespective of BW. Zinc status worsened significantly during early infancy, with infants with BW <2,000 g having the lowest zinc levels.


Subject(s)
Ideal Body Weight , Infant, Low Birth Weight/blood , Infant, Newborn/blood , Mothers , Nutritional Status/physiology , Zinc/blood , Algorithms , Birth Weight , Deficiency Diseases/blood , Deficiency Diseases/diet therapy , Deficiency Diseases/epidemiology , Female , Growth Disorders , Humans , Ideal Body Weight/physiology , India/epidemiology , Infant , Male , Metal Metabolism, Inborn Errors/blood , Metal Metabolism, Inborn Errors/epidemiology , Milk, Human/chemistry , Mothers/statistics & numerical data , Zinc/administration & dosage , Zinc/analysis , Zinc/deficiency
10.
Blood Cells Mol Dis ; 37(3): 192-6, 2006.
Article in English | MEDLINE | ID: mdl-17052926

ABSTRACT

The ferroportin-related disorder is an increasingly recognized cause of hereditary iron overload. Based on the in vitro behavior of different ferroportin mutant subsets, it was suggested that different forms of the disorder might exist in humans. We used MRI to address this question in vivo in 22 patients from four different pedigrees carrying different ferroportin mutations: A77D, N144H, G80S and Val 162del. We found that, based on the iron status of spleen and bone macrophages, two different forms of the disease can be identified: a classic, common form, characterized by hepatocyte, splenic macrophage and bone marrow macrophage iron retention in patients carrying the A77D, G80S and Val 162del ferroportin variants; a rarer non-classic form, associated with liver iron overload but normal spleen and bone marrow iron content in patients with the N144H mutation. The two forms are likely caused by lack- or gain-of-protein function, respectively. Interestingly, in treated patients with the classic form, the spleen and the spine show appreciable iron accumulation even when serum ferritin is normal and liver iron content low. In conclusion, MRI is a useful non-invasive diagnostic tool to categorize and diagnose the disorder, monitor the status of iron depletion and gain insights on its natural history and management.


Subject(s)
Cation Transport Proteins/genetics , Iron Overload/diagnostic imaging , Iron Overload/genetics , Magnetic Resonance Imaging , Metal Metabolism, Inborn Errors/diagnostic imaging , Metal Metabolism, Inborn Errors/genetics , Adolescent , Adult , Aged, 80 and over , Cation Transport Proteins/metabolism , Child , Female , Ferritins/blood , Humans , Iron/blood , Iron Overload/blood , Male , Metal Metabolism, Inborn Errors/blood , Middle Aged , Mutation, Missense , Radiography , Spine/diagnostic imaging , Spine/metabolism , Spleen/diagnostic imaging , Spleen/metabolism
11.
Acta Paediatr ; 95(7): 857-60, 2006 Jul.
Article in English | MEDLINE | ID: mdl-16801185

ABSTRACT

INTRODUCTION: Hyperzincaemia and hypercalprotectinaemia with systemic inflammation, recurrent infections, hepatosplenomegaly, arthritis, anemia, cutaneous inflammation, and failure to thrive is an extremely rare disease and no therapy is reported. AIM: To evaluated the effects of cyclosporine A in hyperzincaemia and hypercalprotectinaemia in terms of serum cytokine level changes before and after treatment. METHODS: A 10-year-old girl was admitted suffering from pyoderma gangrenosum, hepatosplenomegaly, anemia that was unresponsive to iron supplementation, persistent inflammation, arthritis, and increased serum zinc. The level of serum calprotectin was extremely high; therefore, we diagnosed hyperzincaemia and hypercalprotectinaemia and started cyclosporine A treatment. Twelve cytokines in serum were measured before and one year after treatment. RESULTS: Cyclosporine A was very effective. Her skin lesion and joint pain were alleviated and quality of life was markedly improved. C-reactive protein had decreased and anemia had improved. While zinc levels had fallen, calprotectin remained at an extremely high level. Of the cytokines examined, interleukin -6 serum levels had fallen and interleukin -8 showed a marked reduction after treatment. CONCLUSION: Cyclosporine A is effective for hyperzincaemia and hypercalprotectinaemia. Serum interleukin -8 may be useful in assessing the therapeutic effects of cyclosporine A in hyperzincaemia and hypercalprotectinaemia.


Subject(s)
Cyclosporine/therapeutic use , Leukocyte L1 Antigen Complex/blood , Metabolism, Inborn Errors/blood , Metal Metabolism, Inborn Errors/blood , Zinc/blood , Child , Cytokines/blood , Female , Hepatomegaly/blood , Humans , Immunosuppressive Agents/therapeutic use , Inflammation/drug therapy , Pyoderma/blood , Splenomegaly/blood
14.
Pediatr Nephrol ; 17(8): 602-8, 2002 Aug.
Article in English | MEDLINE | ID: mdl-12185465

ABSTRACT

Familial hypomagnesemia, hypercalciuria and nephrocalcinosis (FHHNC) is a rare autosomal recessive inherited disorder that has recently been attributed to a defect in the paracellin-1 ( PCLN-1)gene, encoding for a protein responsible for the tubular reabsorption of magnesium and calcium. Limited information is available on clinical course, therapy and prognosis. We provide information on five patients with FHHNC and their follow-up at our institution. Polyuria, nephrocalcinosis and hyperuricemia were the main clinical findings of a diagnosis at a median age of 4.4 years. The clinical course of PCLN-1 mutations as presented in this study is highly variable, ranging from compensated renal failure to end-stage renal failure - as happened in two of our patients. The progression to renal failure cannot be deduced from the initial presentation. Medical treatment does not appear to influence the progression of the disease. Despite calcium and magnesium substitution, normal values could not be achieved in these patients. Early treatment with vitamin D and calcium was essential to maintain growth. Adequate treatment allows for a normal height and pubertal development.


Subject(s)
Calcium/urine , Magnesium/blood , Membrane Proteins/genetics , Metal Metabolism, Inborn Errors/blood , Metal Metabolism, Inborn Errors/genetics , Nephrocalcinosis/blood , Nephrocalcinosis/genetics , Child , Child, Preschool , Claudins , Diuretics , Female , Follow-Up Studies , Growth/physiology , Humans , Hydrochlorothiazide/therapeutic use , Kidney Function Tests , Male , Mutation/genetics , Nephrocalcinosis/drug therapy , Puberty/physiology , Retrospective Studies , Sodium Chloride Symporter Inhibitors/therapeutic use
15.
Eur J Neurol ; 8(5): 495-9, 2001 Sep.
Article in English | MEDLINE | ID: mdl-11554916

ABSTRACT

We report a patient with isolated familial hypomagnesaemia with hypocalciuria, a rare congenital disorder of magnesium metabolism. During adolescence the patient developed neurological and ophthalmological features not hitherto reported in this condition, including seizures, myoclonus, and retinal pigmentary degeneration. These suggested the phenotype of mitochondrial disease, which has been occasionally reported in association with hypomagnesaemia, but subsequent investigations of mitochondrial function were normal. The pathogenesis of this unusual neurological and ophthalmological syndrome therefore remains uncertain.


Subject(s)
Magnesium/blood , Metal Metabolism, Inborn Errors/blood , Metal Metabolism, Inborn Errors/genetics , Nervous System Diseases/genetics , Adult , Brain/pathology , Calcium/urine , Electromyography , Eye Diseases/complications , Female , Humans , Magnetic Resonance Imaging , Mitochondria/pathology , Phenotype , Retinal Degeneration/complications , Retinal Degeneration/pathology , Seizures/complications
18.
Proc Natl Acad Sci U S A ; 92(7): 2539-43, 1995 Mar 28.
Article in English | MEDLINE | ID: mdl-7708681

ABSTRACT

Ceruloplasmin is an abundant alpha 2-serum glycoprotein that contains 95% of the copper found in the plasma of vertebrate species. We report here on the identification of a genetic defect in the ceruloplasmin gene in a patient previously noted to have a total absence of circulating serum ceruloplasmin in association with late-onset retinal and basal ganglia degeneration. In this patient T2 (transverse relaxation time)-weighted magnetic resonance imaging of the brain revealed basal ganglia densities consistent with iron deposition, and liver biopsy confirmed the presence of excess iron. Although Southern blot analysis of the patient's DNA was normal, PCR amplification of 18 of the 19 exons composing the human ceruloplasmin gene revealed a distinct size difference in exon 7. DNA sequence analysis of this exon revealed a 5-bp insertion at amino acid 410, resulting in a frame-shift mutation and a truncated open reading frame. The validity of this mutation was confirmed by analysis of DNA from the patient's daughter, which revealed heterozygosity for this same 5-bp insertion. The presence of this mutation in conjunction with the clinical and pathologic findings demonstrates an essential role for ceruloplasmin in human biology and identifies aceruloplasminemia as an autosomal recessive disorder of iron metabolism. These findings support previous studies that identified ceruloplasmin as a ferroxidase and are remarkably consistent with recent studies on the essential role of a homologous copper oxidase in iron metabolism in yeast. The clinical and laboratory findings suggest that additional patients with movement disorders and nonclassical Wilson disease should be examined for ceruloplasmin gene mutations.


Subject(s)
Ceruloplasmin/deficiency , Ceruloplasmin/genetics , Iron/metabolism , Metal Metabolism, Inborn Errors/genetics , Amino Acid Sequence , Animals , Basal Ganglia/pathology , Base Sequence , Blepharospasm/blood , Blepharospasm/genetics , DNA/blood , DNA/isolation & purification , DNA Primers , Exons , Female , Humans , Iron/analysis , Magnetic Resonance Imaging , Metal Metabolism, Inborn Errors/blood , Metal Metabolism, Inborn Errors/pathology , Middle Aged , Molecular Sequence Data , Polymerase Chain Reaction , Reference Values , Retinal Degeneration/blood , Retinal Degeneration/genetics , Vertebrates
19.
Magnes Res ; 1(1-2): 79-83, 1988 Jul.
Article in English | MEDLINE | ID: mdl-3274928

ABSTRACT

13 1/2 year old boy with short stature and pubertal delay had infrequent episodes of tetany. Biochemical determinations demonstrated low plasma and high urinary magnesium and potassium levels, hypocalciuria, slightly increased plasma bicarbonate, slightly reduced fractional distal reabsorption of chloride and sodium, high plasma renin activity and high urinary excretion of prostaglandins (E2, F2 alpha). The other parameters of renal functions were normal. Endocrine evaluation of short stature and pubertal delay was normal. Intracellular magnesium and potassium levels in lymphocytes and erythrocytes were within normal limits. Cyclooxygenase blockade with Indomethacin 2.5 mg/kg daily during 4 weeks normalized urinary excretion of prostaglandins and corrected in part low plasma and high urinary potassium levels, but had no effect on magnesium, calcium, sodium and chloride handling. These data raise the possibility that tubular hypomagnesaemia-hypokalaemia could be solely explained by a low renal threshold for magnesium.


Subject(s)
Hypokalemia/physiopathology , Kidney Tubules/physiopathology , Magnesium/blood , Metal Metabolism, Inborn Errors/physiopathology , Potassium/blood , Puberty, Delayed/physiopathology , Adolescent , Erythrocytes/metabolism , Humans , Hypokalemia/blood , Hypokalemia/urine , Indomethacin/therapeutic use , Kidney Tubules/metabolism , Lymphocytes/metabolism , Magnesium/urine , Male , Metal Metabolism, Inborn Errors/blood , Metal Metabolism, Inborn Errors/urine , Potassium/urine , Prostaglandins/urine , Puberty, Delayed/blood , Puberty, Delayed/urine
20.
Gut ; 20(11): 1028-33, 1979 Nov.
Article in English | MEDLINE | ID: mdl-527871

ABSTRACT

A 4 year old male with primary hypomagnesaemia was studied using balance and steady-state perfusion techniques. Magnesium balance was negative and could be accounted for by increased faecal losses, renal conservation being normal; calcium balance was normal. After oral magnesium therapy magnesium balance became positive. The perfusion studies demonstrated net loss of magnesium into the intestinal lumen when low concentrations (1 and 2 mmol/l) of magnesium were perfused in contrast with control subjects; whereas at high concentrations (10 mmol/l a net absorption of a magnitude similar to control values was observed. In the control subjects sequential perfusion of increasing concentrations of magnesium demonstrated a curvilinear relationship between rates of absorption and the lower concentrations (1, 2, and 4 mmol/l) with an apparent Km and Vmax of 4.5 mmol/l and 91 nmol/min/cm respectively. At the higher concentrations (6 and 10 mmol/l) the relationship was linear. These data suggest that two separate transport systems participate in the absorption of magnesium from the proximal small intestine; a carrier-mediated system which saturates at low intraluminal concentrations, and a simple diffusional process. The possibility of the second transport system being a carrier-mediated process with a very much higher Km cannot be excluded. In primary hypomagnaesaemia the results suggest that the primary abnormality is a defect in carrier-mediated transport of magnesium from low intraluminal concentrations of magnesium.


Subject(s)
Intestine, Small/metabolism , Magnesium/metabolism , Metal Metabolism, Inborn Errors/metabolism , Biological Transport , Calcium/metabolism , Child, Preschool , Humans , Intestinal Absorption , Jejunum/metabolism , Kinetics , Magnesium/blood , Male , Metal Metabolism, Inborn Errors/blood , Perfusion
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