Transglutaminase antibodies in children with a genetic risk for celiac disease.

OBJECTIVES: The transglutaminase (TG) antibody test is accurate in identifying celiac disease in symptomatic children. We sought to determine the positive predictive value of this test in asymptomatic children at genetic risk for celiac disease. STUDY DESIGN: Asymptomatic children with a genetic risk for celiac disease were studied to investigate the relationships between TG antibody titer, small bowel histology, growth, and clinical features. Small bowel biopsy histology was graded by using the system of Marsh. RESULTS: Of 30 children with a positive TG antibody test result, 21 (70%) had definite (Marsh score 2 or 3) and 4 (13%) had possible (Marsh score 1) biopsy evidence of celiac disease. TG antibody titer correlated with Marsh score (r = 0.569, P <.01). There was an inverse correlation between Marsh score and height z score (r = -0.361, P =. 05). CONCLUSIONS: In this group of asymptomatic children screened because of a genetic risk, TG antibodies have a positive predictive value of 70% to 83% for biopsy evidence of celiac disease and may identify children before clinical features of celiac disease develop.

Evaluation of school children at high risk for fragile X syndrome utilizing buccal cell FMR-1 testing.

We describe a pilot project utilizing saliva to identify the FMR-1 mutation in high-risk special education students from four public school districts in Colorado. The program included presentations to special education teachers regarding fragile X syndrome, parental consent for testing, completion of a behavior checklist by the teachers, identification of special education students at high risk for fragile X syndrome, subsequent brief examination of face and hands, collection of a saliva sample by either Gatorade swish or brushing of the inside of the cheek, and analysis for the FMR-1 mutation by PCR. Equivocal samples were studied by direct DNA testing using Southern blot analysis, and abnormal results were confirmed by a blood analysis for the FMR-1 mutation. Mutant individuals received genetic counseling and medical and educational assessments to optimize treatment and intervention. This pilot project was met with enthusiasm by the schools. Of the first 439 students evaluated, 68% were male with an average age of 7.75 years; 13% were mentally retarded or autistic. Most students referred for the evaluation were learning disabled (51%) and/or had an Attention Deficit Hyperactivity Disorder (ADHD) (35%). The overall prevalence of the FMR-1 mutation was 5 of 439 or 1.1%. This relatively low yield is probably due to the high number of non-retarded but learning disabled students tested. Of the mentally retarded patients tested, 3.5% were positive for the FMR-1 mutation; however, of the non-retarded or learning disabled patients, only 0.79% were FMR-1 positive.(ABSTRACT TRUNCATED AT 250 WORDS)