The effect of dietary fruits and vegetables on urinary galactitol excretion in galactose-1-phosphate uridyltransferase deficiency

Even on a lactose-restricted diet, urinary galactitol excretion and erythrocyte galactose-1-phosphate levels are persistently elevated in patients with galactose-1-phosphate uridyltransferase deficiency. In order to determine the contribution of galactose in dietary fruits and vegetables to this phenomenon, (1) the content of galactose in a lactose-free diet was directly measured when a galactosaemic patient's diet was specifically enriched in those fruits and vegetables which contain relatively large amounts of free galactose and (2) galactitol excretion was determined during ingestion of this diet for 3 weeks and while on a synthetic diet for 1 week that provided < 8 mg galactose/day. For comparison the effect of a 3-week supplementation of 200 mg galactose/day was determined. The measured intake in total foodstuffs matched the theoretical content of galactose in the patient's diet based on amounts in fruits and vegetables alone, thus supporting the concept that fruits and vegetables are primarily responsible for galactose intake in a lactose-free diet. All of the dietary manipulations, however, had relatively little effect on metabolite levels, suggesting that endogenous galactose production is primarily responsible for the elevated levels of galactose metabolites routinely detected in patients on lactose-restricted diets.

Minimizing false positive diagnoses in newborn screening for galactosemia

Heat and humidity, rather than summertime heat alone, cause extensive loss of galactose-1-phosphate uridyltransferase activity in mailed blood spots and seem to account for false positive diagnoses of galactosemia. The spots are partially protected from the effects of atmospheric humidity if they are allowed to dry and then are sealed in a plastic freezer bag before being exposed to higher humidity. Conversely, extensive loss of transferase activity occurs if the samples are sealed in the bags before the spots are dry. The fluorescence from transferase activity can be monitored with greater sensitivity fluorometrically than visually. A simultaneous fluorometric determination of phosphoglucomutase activity reveals whether decreased transferase activity represents sample deterioration or galactosemia. Mg2+ and a sulfhydryl agent, such as dithiothreitol, are needed for activity of phosphoglucomutase, an enzyme in the sequence leading to the fluorescent substance (NADPH). They must be added in certain modifications of the assay.

[Study of galactose-1-phosphate uridyltransferase activity in erythrocytes of patients with presenile cataract]

In connection with the increased incidence of cataract in middle-aged patients investigations were carried out in order to clear up one of the possible causes of this condition. The detection of a substantial decrease of galactose-1-phosphate uridyl transferase activity in patients with presenile cataract evidences the disturbance of galactose metabolism these patients and allows to accept this genetic defect as the causes of opacification of the lens. Attention was called to the eventual importance of these investigations because of the adoption of a diet without galactose in person threatened+ by cataract could prevent or check this disease.

[Galactose-1-phosphate uridyl transferase and congenital cataract]

The activity of red blood cells galactose-1-p-uridyl transferase (GPUT) was determined by the spectrophotofluorometric method. The average GPUT activity in 102 control subjects was 13. 34 +/- 2. 03u. There were no differences in the sexes and ages. The average GPUT activity in 108 patients with congenital cataract was 11.58 +/- 4. 03u and was lower than that of the controls (P < 0.01). The GPUT activity in 14 of the 108(12.96%)patients was all-3SD below the mean value of the controls (< 7.24u) and the range was from 4.02u to 7.13u with the mean value of 5. 93u being about 44.45% of the normal. The difference between the two groups was statistically significant (P < 0.001). The results indicated that some of the patients with congenital cataract were due to decrease in the GPUT activity. The patients with decrease GPUT activity were mainly suffering from cataracts and their systemic disease were mild.

Florida newborn screening for galactosemia

Galactosemia, an inborn error of metabolism characterized by the inability to transform galactose-1-phosphate into glucose-1-phosphate, occurs in 1:50,000 live births. If not diagnosed and treated within the newborn period, it can lead to severe morbidity and mortality within a few weeks of life. All children in Florida are screened for this disorder by a fluorescence assay system to measure galactose-1-phosphate uridyltransferase (GALT) activity in a dried blood spot. Genetic factors and external forces can affect the activity of the GALT enzyme and lead to confusing results. Parents of infants heterozygous for galactosemia should be offered the opportunity for carrier detection. If both are carriers, genetic counseling should be provided.

Polymorphisms of the enzyme systems galactose-1-phosphate uridyltransferase (GALT) and esterase D (EsD) in the province of Cádiz, southern Spain

Galactose-phosphate uridyltransferase (GALT) and esterase D (EsD) phenotypes were determined by isoelectric focusing in ultrathin-layer polyacrylamide gel (PAGIF) for 406 healthy subjects randomly chosen and residing in the province of Cádiz, in Southern Spain. The following gene frequencies were observed: for GALT, GALT1 = 0.952 970 3 and GALT2 = 0.047 029 71; for EsD, EsD1 = 0.895 320 2, EsD2 = 0.094 827 59, and EsD5 = 0.009 852 21.

[Identification of inborn errors of galactose metabolism in patients with cataracts]

133 patients with congenital or idiopathic cataracts were studied (94 patients had ages between 1 month and 14 years; 10 patients had ages between 16 and 50 years and 29 patients did not have an age registry) along with 18 patients with a clinical diagnosis of classic galactosemia. The activity of galactokinase (GALAK) and that of erythrocyte galactose-1-phosphate uridyl transferase (GALT) was measured. There were no individuals with a total deficiency of GALK or GALT. The cataract patients of ages between 1 monthly and 14 years, 3 (3.19%) and 4 (4.25%) showed GALK and GALT levels in the range corresponding to the respective heterozygotes. As compared with the expected incidence of heterozygotes in the general population (0.2% for GALK and 0.8% for GALT) we found a significant rise of individuals with low levels of enzymes for the metabolism of galactose. The possibility that heterozygote galactosemic states contribute a risk factor in the development of cataracts and its therapeutic implications are discussed.

Evaluation of reduced activity galactose-1-phosphate uridyl transferase by combined radioisotopic assay and high-resolution isoelectric focusing

Fifty-nine patients referred for testing of galactose-1-phosphate uridyl transferase (GALT) activity were evaluated by a combination of radioisotopic assay and an improved high-resolution isoelectric focusing (IEF) method for determination of individual genotypes. The majority of evaluations (43 of 59) were undertaken because of an abnormal fluorometric GALT screening assay conducted as part of a state newborn galactosemia screening program or as a diagnostic test for an infant with one or more clinical signs of galactosemia. Only 12 of the 43 patients with an abnormal fluorometric screening test were found to have less than 3% GALT activity by quantitative assay, no GALT-staining by IEF, and a clinical history consistent with classical galactosemia. The majority of the remainder (24 of 43) were found to be heterozygotes for galactosemia, the Duarte variant, or both. IEF was found to be a fast and accurate technique for assignment of GALT genotypes in conjunction with quantitative enzymatic assay.

Galactose-1-phosphate uridyl transferase in density-fractionated erythrocytes. Studies of normal and mutant enzymes

Galactose-1-phosphate uridyl transferase (GALT), the deficient enzyme in classical galactosemia, was studied by Percoll-gradient age-fractionation of erythrocytes. For normal GALT, a rapid and substantial decrease in GALT activity and loss of most of two isozymes was found to occur in the reticulocyte fractions. The loss of activity was then followed by relative stabilization of both GALT-specific activity and microheterogeneity in mature and aging erythrocytes. When applied to the study of mutant GALT from galactosemic patients, the Percoll-gradient fractionation method permitted detection in the reticulocyte-enriched fractions of up to 5% of normal GALT-specific activity and an isoelectric focusing pattern essentially the same as that of normal GALT. Percoll-gradient fractionation of erythrocytes offers a simple and direct method to study characteristics of GALT activity and microheterogeneity in normal and galactosemic human erythrocytes.

Gonadal failure in young women and galactose-1-phosphate uridyl transferase activity

The present study allows the conclusion that low Gal-1-P transferase activity resulting from GtD/gt heterozygosity is not an major cause of early ovarian failure. However, larger groups of patients need to be examined to fully exclude an association between these rare conditions.

Idiopathic presenile cataract formation and galactosaemia

Five hundred patients undergoing cataract surgery were prospectively examined, and 46 Caucasian patients were found to have strictly idiopathic cataracts severe enough to warrant surgery on or before age 55. In a masked fashion we determined the activity of galactokinase (GK) and galactose-1-phosphate uridyl transferase (GPUT) in these patients as well as on 53 age matched controls. With respect to GK no cataract patient had an enzyme level of less than 2 standard deviations below the control mean. However, 3 of 45 (6.7%) patients in the cataract group had a GPUT level less than 2 standard deviations below the mean for controls, and were presumably heterozygotes for this enzyme. In comparison with the expected population rate of 0.8% this is highly significant (p = 0.006). Abnormalities in galactose pathway enzymes may therefore predispose to development of presenile cataracts. In affected people there is a possibility of treating these patients clinically by dietary restriction of dairy products or by using aldose reductase inhibitors to prevent or reverse cataract formation.

Galactose metabolism in transferase-deficient galactosaemic and normal long-term lymphoid cell lines

The activity (mean +/- SD) of galactose-1-phosphate uridyl transferase in two long-term lymphoid cell lines from Caucasian patients with transferase deficiency galactosaemia, a heterozygote, and eight normal subjects was 0, 78 and 168 +/- 55 nmol UDPG consumed (mg protein)-1h-1, respectively. Also, no activity was found in erythrocytes and cultured fibroblasts from the patients. A small number of cells of the galactosaemic lines cultured in medium, in which galactose was substituted for glucose, survived for 37 days. Normal and galactosaemic lines incubated with D-galactose-[1-14C] liberated 218.2 +/- 65.6 and 18.1 pmol 14CO2 (mg cellular protein)-1 (6h)-1, respectively. The evolution of 14CO2 from D-glucose-[1-14C] was similar in normal and galactosaemic lines. In the presence of [3H]galactose the radioactivity incorporated into TCA-precipitated material of the galactosaemic lines was 6.8% of the normal lines. Approximately 26% and 1.3% of the total radioactivity was incorporated into molecular species with a molecular weight greater than 400,000 daltons in normal and galactosaemic cells, respectively. Similar molecules were identified in the cell-free medium of both normal and deficient cells except for an 18,000 daltons molecule identified only in the medium of the normal cells. These findings indicate that a small amount of galactose is metabolized in galactosaemic lines with no transferase activity.

Polymorphism of human red cell galactose-1-phosphate uridyl transferase in Serbia, Yugoslavia

Phenotypes of human red cell galactose-1-phosphate uridyl transferase (GALT) were determined in 283 unrelated adults from Serbia (Yugoslavia). The gene frequencies were 0.959 for GALT N, 0.018 for GALT D and 0.023 for GALT N.

Application of digital image analysis in cataract retroillumination photography

The Stuttgart digital image analysis system for Scheimpflug photography can be applied without additional extension for pattern recording and densitometric measurements in retroillumination photographic techniques. A preliminary investigation with serial photographs in human cataract showed a large variation in the measured results. Standardisation of photographs taken by the retroillumination technique is not yet possible. For this reason, application of the retroillumination technique is not suitable at this time for clinical longitudinal studies.

Development of a protocol for newborn screening for disorders of the galactose metabolic pathway

The protocol evaluated in this paper employs an enzymatic assay of galactose metabolites, thin layer chromatography, and an assay of galactose-1-phosphate uridyl transferase on a single sample of blood collected routinely for newborn screening. Its effectiveness was tested by a retrospective study of known galactosemic blood samples, and also by a prospective study of 207,000 newborn samples from which 6 infants with severe transferase deficient galactosaemia and 2 infants with red cell epimerase deficiency were identified. The detection rate for severe transferase deficiency in the newborn population was 1:35,000. Advantages include low false positive rate, definitive diagnosis within 6 hours of sample receipt, and the use of technically simple and robust procedures. This protocol overcomes the difficulties encountered with previously described procedures.

Possible role of galactose-1-P-uridyl transferase activity deficiency in red blood cells in the development of the presenile and senile cataract

The activity of red blood cells galactose-1-P-uridyl transferase in 64 patients with presenile and senile cataracts (nondiabetics) and in 41 age-matched controls was investigated. All control subjects examined have shown normal enzymatic levels, while 21.9% of patients with presenile cataracts and 21.7% of patients with senile cataracts presented a statistically significant reduced enzymatic activity (mean +/- 2 SD in controls).

De novo tandem duplication 9p (p12----p24) with normal GALT activity in red cells

A 3 month old boy with a tandem duplication 9p (p12----p24) is reported. Both clinical and dermatoglyphic features were consistent with those of the trisomy 9p syndrome. However, the red cell galactose-1-P uridyl transferase (GALT) activity was normal despite the presence of the duplicated segment 9p13.

Curious neurologic sequelae in galactosemia

Two siblings with classic transferase deficiency galactosemia that was detected at birth have been treated with lactose restriction since the neonatal period. Both patients developed a unique and progressive neurologic syndrome of mental retardation, tremor, and ataxia. Careful review of the family history and medical records, the absence of metabolic disturbances other than those related to galactosemia, and the aggregate physical findings and neurodiagnostic studies ruled out other neurologic disorders in these siblings. It is therefore proposed that these patients represent a subgroup of transferase-deficient galactosemic patients, who develop characteristic neurologic sequelae with conventional dietary management. The existence of this subgroup should be considered in evaluations of therapeutic responses in cohorts of patients with galactosemia. Further, galactosemia should be included in the differential diagnosis of tremor and ataxia in the setting of mental retardation.

Molecular studies on galactose 1 phosphate uridylyl transferase from normal and mutant subjects. An immunological approach

The mutant forms of uridylyl transferase of eight galactosemic patients and two 'Rennes' variants were characterized with regard to the presence and level of immunoreactive protein, the apparent subunit molecular weight and the isoelectric point. Semi-purified haemolysates were studied by various electrophoretic techniques, then proteins were electrophoretically transferred on to nitrocellulose filters. They were treated with specific anti-transferase antibodies, and then with radioiodinated protein A, followed by autoradiography. We have found that: in all cases, a cross-reacting material was detectable, with a molecular subunit size of 46 000, indistinguishable from that of controls. a biochemical heterogeneity of the mutant enzyme was found: the amount of apparent immunologically reactive protein varied from 20 to 100% of that of controls; electrophoretic experiments performed on two 'Rennes' variants showed an increased negative charge.