Elevated serum biotinidase activity in hepatic glycogen storage disorders--a convenient biomarker

An elevated serum biotinidase activity in patients with glycogen storage disease (GSD) type Ia has been reported previously. The aim of this work was to investigate the specificity of the phenomenon and thus we expanded the study to other types of hepatic GSDs. Serum biotinidase activity was measured in a total of 68 GSD patients and was compared with that of healthy controls (8.7 +/- 1.0; range 7.0-10.6 mU/ml; n = 26). We found an increased biotinidase activity in patients with GSD Ia (17.7 +/- 3.9; range: 11.4-24.8; n = 21), GSD I non-a (20.9 +/- 5.6; range 14.6-26.0; n = 4), GSD III (12.5 +/- 3.6; range 7.8-19.1; n = 13), GSD VI (15.4 +/- 2.0; range 14.1-17.7; n = 3) and GSD IX (14.0 +/- 3.8; range: 7.5-21.6; n = 22). The sensitivity of this test was 100% for patients with GSD Ia, GSD I non-a and GSD VI, 62% for GSD III, and 77% for GSD IX, indicating reduced sensitivity for GSD III and GSD IX, respectively. In addition, we found elevated biotinidase activity in all sera from 5 patients with Fanconi-Bickel Syndrome (15.3 +/- 3.7; range 11.0-19.4). Taken together, we propose serum biotinidase as a diagnostic biomarker for hepatic glycogen storage disorders.

Hepatic ultrasound findings in the glycogen storage diseases

Hepatic ultrasonography was performed on 70 patients with the hepatic glycogen storage diseases (GSDs) to assess parenchymal echogenicity. 27 patients had GSD-I, 24 had GSD-III and 19 had GSDs-VI/IX; ages varied from 0.6 to 35.7 years (median 11.7). 31 (44%) had normal or mild parenchymal changes, and 41% (11/27) of those with GSD-I, 25% (6/24) with GSD-III and 11% (2/19) with GSDs-VI/IX had marked changes. No relationships were found between the ultrasonographic appearances and other indices of metabolic control, including plasma triglycerides, total cholesterol or height standard deviation score. Seven adult patients (21-29 years) were found to have hepatic tumours: six with GSD-I and one with GSD-III. Those with GSD-I and tumours tended to have the more severe hepatic parenchymal changes. We conclude that ultrasonography may be useful in identifying patients with GSD-I at risk of hepatic tumour formation.

[Hepatic glycogenosis: the clinical, biochemical and enzymatic aspects in a group of pediatric patients]

Nine children with clinical diagnosis of glycogenoses were studied, types were confirmed through determination of levels and structure of glycogen, stimulation with glucagon and enzymatic defect analyses. Eight patients suffered glycogenoses type III and one, type VI. The major age group un type III was 1 to 2 years old (62.5%), the type VI was diagnosed in a preschool boy. Mean clinical features were: hepatomegaly, doll-like facies and short height. Major biochemical alterations were: transaminases elevation in both types, hypertriglyceridemia, hyperglycemia, metabolic acidosis and hyperuricemia only in glycogenoses III. One III type patient presented cardiovascular alterations. All patients showed increased concentrations of erythrocyte glycogen, with normal structure in type VI and abnormal in 75% of type III. Tree fourths of type III patients had a positive response to glucagon stimulation. No one presented glucose 6 phosphatase deficiency.

[Hemoglobin A1 in hypoglycemias in childhood]

The average HbA1 concentrations of 20 patients with hypoglycaemic diseases were not significantly different from metabolically healthy controls. There was also no correlation between the HbA1 and the blood glucose levels of these patients. Remarkably, two patients which responded to therapy with an increase of blood glucose showed also an increase of HbA1.

Isoenzyme pattern of phosphorylase in white blood cells and fibroblasts from patients with liver phosphorylase deficiency

Isoenzyme patterns of phosphorylase in white blood cells and cultured fibroblasts of a patient affected with liver-type phosphorylase deficiency were studied. Three bands were observed with electrofocusing of white blood cells and liver from controls. In the white blood cells of the patient only two bands were observed. Patient and control fibroblasts showed two bands, probably identical to the two bands observed in the patient's white blood cells. These results indicate that the liver-type phosphorylase is not expressed in the cultured fibroblasts.