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Familial Hypophosphatemia
Studies on its Pathogenesis in an Affected Mother and Son
- GEORGE J. MAGID, M.D., F.A.C.P.;
- JOHN R. MALONEY, M.D.;
- JONAS H. SIROTA, M.D., F.A.C.P.; and
- EDWARD A. SCHWAB, JR., B.A.
- Requests for reprints should be addressed to George J. Magid, M.D., Department of Medicine, Santa Clara County Hospital and Medical Center, 751 South Bascom Ave., San Jose, Calif. 95128.
Excerpt
An increasing number of reviews have described the clinical, laboratory, and X-ray findings of a form of rickets or osteomalacia similar to that due to vitamin D deficiency and resistant to ordinary doses of vitamin D. The main biochemical abnormalities are hypophosphatemia, normal or slightly reduced serum calcium concentrations, and in most cases, elevated serum alkaline phosphatase concentrations. Except for elevated renal phosphate clearances and rare instances of associated amino-aciduria or glycosuria, renal function has been shown to be normal. No other evidence of renal tubular dysfunction has been noted.
The most consistent characteristic in all of the reported cases
Acknowledgments
The authors are indebted to Dr. Donald McMillan, Assistant Chief of Medicine and Director of the Metabolic Unit, United States Public Health Service Hospital, San Francisco, Calif., for his advice and critical review of the manuscript. Dr. Ruth Illig, Department of Pediatrics, Stanford University Medical Center, supervised the urinary chromatographic studies. Mrs. Carol Pastor and Mrs. Patricia Stephenson of the Santa Clara County Hospital Dietary Department supervised all of the diets used in this study.
Summario in Interlingua
Le pathophysiologia de hypophosphatemia familial esseva studiate in un matre de 46 annos de etate e su filio de 16 annos de etate qui es ambes victimas del morbo. Initialmente, le functionamento cardiac, hepatic, e renal esseva normal. Hyperphosphaturia esseva presente in ambe subjectos, e glucosuria—confirmate per studios chromatographic—accompaniava le perditas de phosphato in le filio. Le maxime resorption tubular de glucosa esseva normal in le matre (322 mg/min) e reducite in le filio (286 mg/min). Le clearance de phosphato remaneva inalterate durante le determination del maxime reabsorption tubular in ambe patientes.
A comparabile cargas filtrate, le reabsorbite phosphato esseva reducite in ambe patientes. Illo esseva, in le matre e in le filio, respectivemente, 67,5 e 79,2 µ mol/min/100 ml de filtration glomerular, durante que le correspondente cifras ab 3 similemente testate subjectos normal esseva 115, 120, e 124.
Le excretion de nitrogeno alpha-aminic esseva normal in ambe patientes, i.e., 96 e 194 mg per 24 horas in le matre e in le filio, respectivemente, con normal configurationes de amino-acidos.
Infusiones de calcium (15 mg/kg) un de 3 horas e duo de 6 horas, effectuate consecutivemente, non afficeva le clearance de phosphato o le centuplicate proportion del clearances de phosphato e creatinina in o le un o le altere del patientes. In 10 subjectos normal testate con similemente constante infusiones de calcium de 15 mg/kg, le clearance de phosphato declinava 9 vices per plus que 58 pro cento, e le centuplicate proportion del clearance de phosphato e creatinina declinava 10 vices per inter 44 e 97 pro cento.
Sensibilitate pro infusiones de exogene hormon parathyroide esseva demonstrate in ambe patientes al nivellos de 25 e 200 unitates de extracto parathyroide.
Iste studios pare justificar le sequente conclusiones: (1) Le escappamento de phosphato in iste patientes es le consequentia de un intrinsec defecto renal. (2) Le phosphaturia es augmentate per exogene hormon parathyroide. (3) Le reabsorption de glucosa e de phosphato es mutualmente independente.
Article and Author Information
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From the Metabolic Clinic, Department of Medicine, Santa Clara County Hospital and Medical Center, and the Santa Clara Medical Center Research Foundation, San Jose, Calif.
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This study was supported by grant AM-07383 from the National Institutes of Health, Bethesda, Md., with the assistance of a grant from the Santa Clara County Heart Association.
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- Received November 22, 1965.
- Accepted January 24, 1966.
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