We screened 183 autistic males for the fra(X) and found 24 (13.1%) to be positive. Adding the subjects of this study to those of 11 other surveys, of which 6 were positive and 5 were negative, a total of 614 autistic males have been screened. Overall 47 (7.7%) were positive. Based on this estimate and the prevalence of autism and fra(X), we estimate that 12.3% of fra(X) males are autistic. We have found that 17.3% of our fra(X) males were autistic and overall a 21.2% frequency has been reported, these higher figures are most likely due to biases in age and ascertainment. With an overall 7.7% frequency of fra(X) among autistic males and an estimated 12.3% of autism among fra(X) males, we conclude there is likely to be a significant association of fra(X) with autism. Because fra(X) appears to be the single most common cause of the condition, chromosomal testing is recommended for any autistic person with undiagnosed etiology.

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The continuing increase in the incidence of type 2 diabetes mellitus (DM2) and obesity in children and adolescents is attributable to excessive caloric intake. Abnormal lipid metabolism in the postprandial state leads to long exposure of the vasculature to hyperlipidemia. Most children and adolescents with DM2 are obese, and many have fasting hypertriglyceridemia. Clustering of hyperlipidemia, DM2 and obesity increases the risk for cardiovascular disease. We therefore studied lipids, insulin, C-peptide, and glucose in response to an oral fat load simulating the fat content of a high-fat, fast-food meal in 12 type 2 diabetic obese, 15 non-diabetic obese, and 12 non-diabetic non-obese (control) adolescents (aged 10-19 yr; 87% African-Americans). All three groups were age-, sex-, and sexual maturation-matched. Mean body mass indices were similar in the diabetes and obese groups (32.7 +/- 1.1 vs 35.8 +/- 1.6 kg/m2). All patients with DM2 had fasting C-peptide > 0.2 nmol/l (0.7 ng/ml) and negative diabetes-associated autoantibodies. Serum total cholesterol, triglyceride, high- and low-density lipoprotein cholesterol, insulin, C-peptide, and plasma glucose levels were measured at 0, 2, 4, and 6 h after the fat load. The area under the curve (AUC) was calculated by trapezoidal estimation. Triglyceride AUC was significantly greater in the diabetes group than in the other two groups (15.7 +/- 2.9 vs 9.2 +/- 0.7 and 7.5 +/- 0.7 mmol x h/l [1389 +/- 258 vs 819 +/- 60 and 663 +/- 62 mg x h/dl]; p < 0.02 and <0.004, respectively), as were insulin, C-peptide, and glucose AUCs. Incremental triglyceride response (delta triglyceride = peak - fasting) in the diabetes group was significantly higher than that in the control group (2.1 +/- 0.7 vs 0.8 +/- 0.1 mmol/l 189.7 +/- 58.4 vs 71.2 +/- 11.1 mg/dl]; p < 0.04). Insulin resistance was estimated using the homeostasis model assessment (HOMA), which was greater in the diabetes group than in the obese and control groups (14.4 +/- 2.8 vs 5.2 +/- 0.8 and 3.2 +/- 0.4; p < 0.001 and < 0.0001, respectively). The diabetes group was divided into subgroups of high and normal fasting triglycerides on the basis of triglyceride levels above and below the 95th percentile. The delta triglyceride in the subgroup with high fasting triglycerides was substantially greater than in the subgroup with normal fasting triglycerides (3.4 +/- 1.1 vs 0.8 +/- 0.2 mmol/l [305.2 +/- 96.8 vs 74.2 +/- 18.0 mg/dl]; p < 0.001). Total cholesterol and triglyceride AUCs were much greater in the high vs normal fasting triglycerides subgroup (33.0 +/- 2.9 vs 24.2 +/- 1.9 and 23.6 +/- 3.5 vs 7.8 +/- 0.6 mmol x h/l [1274 +/- 113 vs 934 +/- 72 and 2085 +/- 309 vs 692 +/- 49 mg x h/dl]; p < 0.02 and <0.0001, respectively), as were insulin and C-peptide AUCs. HOMA was greater in the high vs normal fasting triglycerides subgroup (20.8 +/- 4.0 vs 8.0 +/- 1.6; p < 0.0001). In addition to elevated plasma glucose levels, there were no significant differences in either insulin or lipid parameters among the diabetes subgroup with nor...

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The present study was conducted to determine the extent of insulin deficiency and glucagon excess in the hyperglycemia of type 2 diabetes in children. The incidence of type 2 diabetes mellitus in children and adolescents has increased substantially over the past several years. Because insulin and glucagon action both regulate blood glucose concentration, we studied their responses to mixed meals in children with type 2 diabetes. Subjects were 24 patients with type 2 diabetes compared with 24 controls, aged 9--20 yr (predominantly African-Americans), matched for body mass index and sexual maturation. All of those with diabetes were negative for antibodies to glutamic acid decarboxylase. Plasma glucose, glucagon, and serum C-peptide concentrations were measured at 0, 30, 60, 90, and 120 min after a mixed liquid meal (Sustacal) ingestion (7 mL/kg body weight; maximum, 360 mL). The area under the curve (AUC) was calculated by trapezoidal estimation. The incremental C-peptide (Delta CP) in response to the mixed meal was calculated (peak -- fasting C-peptide). The plasma glucose AUC was significantly greater in patients than in controls (mean +/- SEM, 1231 +/- 138 vs. 591 +/- 13 mmol/L x min; P < 0.001). The Delta CP was significantly lower in those with diabetes than in controls (1168 +/- 162 vs. 1814 +/- 222 pmol/L; P < 0.02). Glucagon responses did not differ between the two groups. Hyperglycemia is known to inhibit glucagon secretion. Therefore, our patients with substantial hyperglycemia would be expected to have decreased glucagon responses compared with controls and are thus relatively hyperglucagonemic. Patients were divided into poorly and well controlled subgroups (glycosylated hemoglobin A(1c), > or =7.2% and <7.2%, respectively). There were no significant differences in the Delta CP and glucagon responses between these two subgroups. We next analyzed the data in terms of duration of diabetes (long term, > or =1 yr; short term, <1 yr). The CP was significantly lower in long- vs. short-term patients (768 +/- 232 vs. 1407 +/- 199 pmol/L; P < 0.05). The plasma glucagon AUC was significantly higher in the long- vs. short-term patients (9029 +/- 976 vs. 6074 +/- 291 ng/L x min; P < 0.001). Hemoglobin A(1c) did not differ between long- vs. short-term patients. Our results indicate that relative hypoinsulinemia and hyperglucagonemia represent the pancreatic beta- and alpha-cell dysfunctions in children with type 2 diabetes. The severity of both beta- and alpha-cell dysfunctions appears to be determined by the duration of diabetes.

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In a patient with the Lesch-Nyhan syndrome we found decreased spinal fluid 5-hydroxyindole acetic acid (5-HIAA), the major metabolite of serotonin, and decreased homovanillic acid (HVA), the major metabolite of dopamine, indicating a decrease in monoamine metabolism. Administration of 5-hydroxytryptophan and carbidopa produced an increase in spinal fluid 5-HIAA, indicating that it might be possible to correct the serotonin deficiency in this syndrome, but there were no changes in the marked mental retardation and neurological deficits. Self-mutilation appeared to be suppressed by therapy but the effectiveness of the drugs decreased with time. There were also changes in the spinal fluid concentration of amino acids that might affect brain protein synthesis. These changes were corrected during administration of 5-hydroxytryptophan and carbidopa.

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