Fatty acid status in treated galactosaemia

Neurodevelopmental problems in patients who have been treated early for galactose- 1-phosphate uridyltransferase deficiency (classical galactosaemia, McKusick 230400) are quite common, even when the dietary therapy is not delayed and is apparently well followed (Komrower 1982). Removing dairy products from the diet does not seem to reduce the incidence of the deleterious outcomes. Thus, new studies in biochemical, endocrinological and genetic parameters are needed. We checked in treated galactosaemics the status of the major n-3, n-6 and n-9 unsaturated fatty acids (FA) critical for the development of growing tissues, particularly the central nervous system (Martinez 1992). Cases included 5 subjects (3 male and 2 female, aged 3-14 years) treated from the first month of life for classical galactosaemia, whose anthropometric indices averaged the 50th centile both for weight and height. Controls consisted of 8 subjects (6 male and 2 female, aged 3-14.5 years), clinically healthy and on a free diet. For each subject, weight was appropriate for height. In both groups the macronutrient supply was investigated by a 24-h recall. A blood sample was drawn after an overnight fast to determine circulating lipid levels and the FA composition of plasma and erythrocyte phospholipids. Circulating plasma lipids (total and high-density lipoprotein cholesterol, triglycerides, phospholipids) were determined through enzymatic methods. For measurement of FA levels, lipids were extracted with chloroform-methanol (Folch) and phospholipids were separated by thin-layer chromatography. FA methyl esters were analysed with a model 4160 Carlo Erba gas chromatograph equipped with Supelcowax 10 capillary column and were expressed as weight percentages. The analysis of the nutrient supply showed lower protein and saturated fat and higher monounsaturated fat intake in galactosaemics; the calorie supply was similar in both groups. No differences were detected between groups for any of the lipidic classes. As regards the FA status, galactosaemics exhibited higher oleic acid (18:1 n-9, median 12.5%, range 10.9-13.2%, vs median 10.3%, range 8.49-12.0% in controls, p < 0.05 (Mann-Whitney U-test)) and lower eicosapentaenoic acid (20 : 5 n-3, median 0.25%, range 0.18-0.41%, vs median 0.43%, range 0.12-0.79% in controls, p < 0.05) levels in plasma phospholipids. No significant differences were present in the FA composition of erythrocyte phospholipids. Milk and dairy products are rich in saturated fats, so their avoidance could be at the origin of the differences in the dietary habits and in the phospholipid level of 18:1 n-9 FA in galactosaemics. Nevertheless, in contrast to other metabolic disorders (Holman and Johnson 1981; Galli et al 1991), the FA status of subjects treated for classical galactosaemia seems to be minimally affected by the dietary treatment and/or the metabolic defect. The observed differences should not have a role in the clinical course of the disease.