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ARS Home » Plains Area » Houston, Texas » Children's Nutrition Research Center » Research » Publications at this Location » Publication #98189
Title: CALCIUM ABSORPTION IS NORMAL IN GIRLS WITH RETT SYNDROME

Author
item SCHULTZ, REBECCA - BAYLOR COLL OF MEDICINE
item Motil, Kathleen
item Abrams, Steven
item GLAZE, DANIEL - BAYLOR COLL OF MEDICINE

Submitted to: Pediatric Research
Publication Type: Abstract Only
Publication Acceptance Date: 2/19/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Background: Girls with Rett Syndrome (RS) are at increased risk for osteopenia and skeletal fractures. Alterations in body calcium (Ca) metabolism or its hormonal regulation may contribute to their bone abnormalities. Objectives: To determine if reduced rates of intestinal Ca absorption, increased rates of urinary Ca excretion, or alterations in parathyroid (PTH) and vitamin D hormones account for osteopenia in RS. Methods: We characterized body (Ca) metabolism in 8 RS girls and 10 healthy controls (C). The percentage of dietary Ca absorbed was determined by the duel isotope tracer technique. All subjects received an oral dose of 46Ca and an intravenous (IV) dose of 42Ca. Urine samples were collected for 24-h to determine the isotopic enrichment and concentration of Ca by thermal ionization mass spectrometry and flame atomic absorption spectroscopy. Urine Ca loss (UCL) was calculated as the product of total urine volume and Ca concentration. The percentage of dietary Ca absorbed (PCA) was calculated from the relative urinary excretion of oral and IV administered Ca isotopes. The amount of food consumed was determined by test-weighing all meals. The Ca content of the food was estimated from a nutrient database. The rate of Ca absorption (RCA) was calculated as the product of PCA and Ca intake. Net Ca retention (NCR) was calculated as the differences between Ca intake and intestinal, urinary, and miscellaneous losses. Conclusions: Dietary Ca intake, PCA, RCA, UCL, NCR, and PTH and VD levels were not different between RS and healthy girls. Neither intestinal malabsorption, increased urinary losses, nor inadequate dietary intakes of Ca account for the osteopenia associated with RS.