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We report two unrelated cases of adult galactosaemia females with normal ovarian function and Q188R/R333G mutations. Clinical history has been followed for 40 years. Biochemical finding in one patient are consistent with the presence of small amounts of galactose-1-phosphate uridyltransferase (GALT) activity, which differs from classical galactosaemia.

Existing longitudinal data on patients with classical galactosaemia suggests that neurocognitive functioning is impaired and, in isolated case reports, may show a decline in performance over time. The present study explored whether there are long-term changes in cognitive abilities in patients with galactosaemia and whether oral uridine can improve neurocognitive performance. Thirty-five patients (18 males, 17 females), 29 of whom received oral uridine powder at 150 mg/kg per day (divided dose, three times daily), were evaluated over a 2-5-year period with the Woodcock-Johnson Revised Cognitive Abilities Test, three academic achievement tests, and the Beery Test of Visual Motor Integration. Results showed that the uridine cohort and a comparison group that received only dietary restriction made small gains in cognitive performance over the treatment period and the size of the gains did not differ significantly. Seven subjects who started uridine prior to the age of 14 months did not differ significantly in their cognitive test scores at an average age of 3.5 years from a group of older children who had begun treatment at 4.5 years of age. These results provide no support for any developmental or uridine-treatment-related change in cognitive functioning for this sample of galactosaemic subjects.

A sensitive radioisotopic method has been developed which can detect galactose-1-phosphate uridyltransferase (GALT) activity as low as 0.1% of normal control values in both erythrocytes and leukocytes. This assay utilizes carbon-14 labeled galactose-1-phosphate with high specific activity and requires removal of endogenous galactose-1-phosphate (Gal-1-P) and uridine diphosphate glucose (UDPGlc) through dialysis. Optimal exogenous UDPGlc concentration has been determined with a fixed concentration of Gal-1-P in the incubation. The rate of product, uridine diphosphate galactose (UDPGal), formation is monitored at three different times. Among 423 patients with galactosemia studied by this method, 363 patients exhibited no detectable GALT activity in their erythrocytes and 60 patients were found to have detectable erythrocyte GALT activity ranging from 0.02 to 5.0 units normal values: > 20 units). The former group of patients was designated as classic galactosemia (GG) and the latter group as galactosemia variant (GV). Leucocytes from ten patients belonging to the GG group also showed complete absence of GALT activity while leukocytes from two patients belonging to the GV group showed GALT activity at levels comparable with those found in their erythrocytes. Because there is extensive biochemical heterogeneity among galactosemia patients, we recommend that an assay with increase sensitivity be carried out on blood samples from galactosemia patients so that clinical, biochemical and molecular correlations made by different groups of investigators can be compared.

A historical group of 45 children (4-18 years) and adults (18-39 years) with classical galactosemia had deficits of cognitive function that were variable and not related to the age at diagnosis or to severity of illness at presentation. There was a trend for patients to score highest on visual processing tasks. The standardized tests of speech and memory skills fell within the same range as the Broad Cognitive Ability score, indicating that the speech and language deficits may be part of a more global set of cognitive impairments. Scores on the Beery Visual Motor Integration and Block Design Tests fell in approximately the same range as other cognitive abilities. In addition, there was a high incidence of abnormality detected on MRI and 12 patients had neurologic symptoms that included ataxia, tremor and dysmetria. These abnormalities did not correlate with the age at diagnosis, severity of illness at presentation or scores on cognitive testing. The pathophysiology of neurologic and neuropsychologic impairments remains unknown. Since these appear to be unrelated to the duration of galactose exposure, other factors impacting on outcome need to be understood so that strategies can be developed to improve what appears to be a global impairment of cognitive function.

In classic galactosemia, long-term neurologic sequelae can include low cognitive functioning and a curious neurologic syndrome with tremors, dysmetria, and ataxia. An abnormal white-matter signal on cerebral magnetic resonance imaging (MRI) is present in almost all patients; some have mild cerebral or cerebellar atrophy and focal white-matter lesions. The present study was undertaken to assess the integrity of myelinated pathways by recording somatosensory evoked potentials. Results were correlated with age at diagnosis, severity of illness, age at evoked potentials, neurologic examination, MRI studies and cognitive outcome as measured by the Woodcock-Johnson Revised Standard Cognitive Battery. Evoked potentials were abnormal in 17 (28%) of 60 patients who had median nerve, and 26 (77%) of 34 patients who had posterior tibial nerve studies. Abnormalities of the central rather than the peripheral nervous system were most common. Evoked potentials correlated with severity of presenting symptoms (P = .011), age at evoked potential testing (P = .029), and presence of focal white-matter lesions on MRI (P = .049). Results of neurophysiologic testing showed no correlation with the Woodcock-Johnson Battery. Patients with classic galactosemia may have abnormal conduction along myelinated pathways that is associated with other central deficits. Myelin, which contains galactose, may be adversely affected in this inborn error of metabolism.

We evaluated 132 galactosemia patients for the Q188R (glutamine-188 to arginine) mutation in the human galactose-1-phosphate uridyltransferase (GALT) gene and for GALT activity in their hemolysates by a sensitive radioisotopic method. In those without any detectable GALT activity (GG), the Q188R mutation constituted 67% of the alleles. In patients with detectable GALT activity (GV), only 16% of the alleles were accounted for by Q188R. In all patients who were homozygous for the Q188R mutation, no erythrocyte GALT activity could be demonstrated. There was an extensive variation in the amount of detectable GALT activity ranging from 0.1% to 5% of the normal values among the GV patients. There was a difference in the frequency of Q188R mutation in the GALT alleles among patients belonging to different racial and ethnic groups. In Caucasian and Hispanic patients, the frequency was not far different (64% and 58%, respectively). On the other hand, only 12% of the GALT alleles with Q188R were found in African-American patients.

This study was conducted to determine whether there is a genotype/phenotype correlation between aspects of cognitive, neurologic, and ovarian outcome in patients with galactosemia and the Q188R mutation of the galactose-1-phosphate uridyltransferase gene. The results showed that the Q188R mutation was found in 72% of alleles: 38 patients were homozygous and 21 were heterozygous for Q188R; eight patients did not have the mutation. The mean Broad Cognitive score for the group homozygous for Q188R was 75 (SD = 16), which was not statistically different from the outcome for the heterozygous group (mean score, 67; SD = 25) or the negative group (mean score, 88; SD = 21). Tremor, ataxia, and dysmetria were found in 12 subjects, and there was no association with Q188R status. Similarly, there was no association of this mutation with the development of primary amenorrhea (8 subjects) versus secondary amenorrhea (found in 14 women). Our findings suggests that the variability of outcome for patients with classic galactosemia cannot be explained by Q188R status alone, at least with regard to cognitive functioning, presence of neurologic symptoms, and timing of the onset of ovarian failure.

A survey of 108 heterozygote women for the classic galactosemia gene, GALT, did not reveal that the carrier state was associated with premature ovarian failure or ovarian cancer. This survey did not support previous epidemiologic studies suggesting an increased risk for ovarian dysfunction in women with deficiency of the GALT enzyme.

Forty children and adults with classic galactosemia had vertebral bone density determined by standard quantitative computed tomography at 3.4 to 44.2 years of age. Compared with age- and sex-matched control subjects, patients with galactosemia had diminished bone density (p = < 0.001). Prepubertal patients of both sexes had bone density determinations below those of the control group (p = 0.008); similar findings were seen in postpubertal patients as well (women, p = 0.001; men, p = 0.008). Women receiving replacement estrogen-progestin therapy for premature ovarian failure had abnormal bone density (136.3 +/- 17.3 mg/cm3 vs 166.0 +/- 17.5 mg/cm3 for control subjects; p = 0.002); patients with evidence of ovarian insufficiency not receiving replacement sex steroids had even lower bone density (92.4 +/- 14.3 mg/cm3 vs 160.2 +/- 20.2 mg/cm3 for control subjects; p < 0.001). Calcium intake for the entire galactosemia group was 540 +/- 344 mg/day. Calcium intake correlated positively with bone density in women given exogenous estrogen (r = 0.87; p = 0.002) and in men (r = 0.74; p = 0.009). Thus the diminished mineralization of bones appears to be another abnormality associated with galactosemia. The results of our study suggest that this is likely secondary to abnormal levels of sex steroids in female patients, low calcium intake, and perhaps an intrinsic defect in the normal galactosylation of the collagen matrix of bone caused by the enzyme defect. Strategies to improve bone formation should be considered to diminish morbidity in patients with this inborn error of metabolism.

The cerebral findings at magnetic resonance imaging in 67 transferase-deficient galactosemic patients (36 female, 31 male; median age, 10 years) are reported. Twenty-two patients had mild cerebral atrophy, eight had cerebellar atrophy, and 11 had multiple small hyperintense lesions in the cerebral white matter on T2-weighted images. The classic galactosemic patients (those without measurable transferase activity) older than 1 year of age did not show the normal dropoff in peripheral white matter signal intensity on intermediate- and T2-weighted images. The authors postulate that this abnormal signal intensity is due to altered myelin formation secondary to the inability to make sufficient and/or normal galactocerebroside.

In summary, oocyte and pre-embryo donation may be used to establish pregnancy in women with galactosemia and ovarian failure. Reported is the first pregnancy after pre-embryo donation to a woman with classical galactose-1-phosphate uridyl transferase deficiency. Despite disturbances in galactose metabolism, the endometrial lining responded normally to exogenous hormone replacement and was receptive to pre-embryo implantation. Pregnancy support was provided by exogenously administered oral E2 and IM P for the initial 100 days, at which time placental hormone production solely maintained the gestation.

Evaluation of ovarian steroid secretion, histologic examination of ovarian tissue, and incubation studies with radiolabelled galactose in ovarian tissue slices were performed in a 21-year-old woman with galactosemia and incipient ovarian failure. After exogenous gonadotropin administration in an attempt to achieve fertility, there was no evidence of ovulation by ultrasound; estrogen and androgen production were deficient indicating ovarian unresponsiveness. Histologic examination of the ovary revealed that the ovarian stroma had an increase in fibrous tissue and that a few hyalinized atretic follicles were present with no intermediate or evolving Graafian follicles. After incubation with galactose-1-14C, there was absence of labelled CO2 production and only labelled galactose-1-phosphate was identified as compared to controls in which several labelled intermediates could be seen. The incorporation of galactose into the TCA-insoluble fraction was drastically reduced in the patient compared to controls, suggesting that there may be a deficiency of ovarian galactose-containing glycolipids, glycoproteins and mucopolysaccharides in the galactosemic ovary. Deficiency in the production of galactose containing compounds, or galactose-1-phosphate accumulation or both, may lead to the development of hypergonadotropic hypogonadism seen in women with galactosemia.

We evaluated gonadal function in 18 female and eight male patients with galactosemia due to transferase deficiency; it was normal in the males, but 12 females had signs of hypergonadotropic hypogonadism. All female patients had a 46,XX karyotype, normal levels of thyroid hormone and prolactin, and no anti-ovarian antibodies. The biologic activity of urinary gonadotropins was normal. Ultrasonography of the pelvis revealed that ovarian tissue was diminished or absent. Total estrogens increased in one of two patients after administration of human menopausal gonadotropin. The frequency of hypergonadotropic hypogonadism was higher in females in whom dietary treatment for galactosemia was delayed. Clinical course and mean erythrocyte galactose-1-phosphate and urinary galactitol levels did not correlate with ovarian function. We conclude that female patients with galactosemia have a high incidence of ovarian failure due to acquired ovarian atrophy. Galactose or its metabolites may be toxic to the ovarian parenchyma, particularly during the immediate neonatal period.

Gonadal function was followed in 26 females and 12 males with galactosaemia due to deficiency of the enzyme galactose-1-phosphate (Gal-1-P) uridyl transferase over a 4 year period. Gonadal function was normal in males, but all females except two had evidence of acquired ovarian failure. Twelve females with ovarian failure documented at the beginning of this study continued to have either primary or secondary amenorrhoea on follow-up. Five of six patients, who previously had normal gonadal function developed either hypergonadotrophic hypogonadism or an abnormal response to gonadotrophin-releasing hormone (LRH) indicative of acquired ovarian damage. Seven of eight female patients, 1-12 years of age, who were evaluated for the first time had an exaggerated release of gonadotrophins during LRH stimulation tests diagnostic of gonadal insufficiency. The pathogenesis of ovarian failure remains unknown, but it appears likely that galactose or Gal-1-P is toxic to the ovary. The source of galactose metabolites, which may begin to accumulate prenatally and continue to damage the gonad in the postnatal period, is likely to be derived from the diet and from the endogenous synthesis of Gal-1-P from glucose via a variety of metabolic pathways. The testis appears to be relatively resistant to the effects of abnormal galactose metabolism.

The levels of uridine diphosphate galactose (UDPGal) and uridine diphosphate glucose (UDPGlc) have been determined in liver autopsy samples, erythrocytes and cultured skin fibroblasts from galactosaemic patients and compared to non-galactosaemic controls. In patients with undetectable erythrocyte galactose-1-phosphate uridyltransferase (transferase) activity, the levels of UDPGal were substantially lower than in controls. In patients with detectable transferase activity, even though in less than 1% of normal values, both UDPGal and UDPGlc levels were in the normal range. Incubation of erythrocytes from both galactosaemic patients and normal individuals with 10 mmol/L uridine increased UDPGal and UDPGlc levels several-fold, both in the presence or absence of galactose in the incubation medium. We hypothesize that a deficit of UDPGal is responsible for the late onset clinical manifestations in galactosaemia which include ovarian failure, speech defect and neurological abnormalities. We suggest that uridine administration may be of therapeutic value in raising the intracellular concentrations of UDPGal. We conclude that the transferase reaction, however small in activity, is essential for optimal UDPGal formation.

Galactose metabolism was studied in human ovarian tissue obtained from 14 women controls between 21 and 72 y of age, and one 21-y-old galactosemic patient with hypergonadotrophic hypogonadism. Tissue slices were incubated with 1-14C-galactose, and labeled intermediates were analyzed by anion-exchange column chromatography. Activities of enzymes related to the galactose pathway: galactokinase, transferase, epimerase, uridine diphosphoglucose (UDPGlc) and uridine diphosphogalactose pyrophosphorylases, and UDPGlc and uridine diphosphogalactose pyrophosphatases were measured in ovarian homogenates using radioisotopic, spectrophotometric, and fluorometric techniques. Incorporation of carbon label from 1-14C-galactose into various galactose and glycolytic intermediates, as well as carbon dioxide and TCA-insoluble materials was demonstrated in samples from non-galactosemic controls. In tissue from the galactosemic individual, no labeled carbon dioxide was produced and very little incorporation into TCA-insoluble material was found. Labeled galactose-1-phosphate was elevated. In normal ovarian tissue, specific activities of galactokinase, transferase, epimerase, and UDPGlc pyrophosphorylase are much higher than those found in the red cells and in testes. UDPGlc pyrophosphorylase activity is about 50 times that of transferase, suggesting that uridine nucleotide sugars have an important role in the normal development and function of the ovary. It is hypothesized that premature ovarian failure, often observed in patients with galactosemia, is due to interference with nucleotide sugar metabolism and the synthesis of galactose containing glycoproteins and glycolipids consequent to the enzymatic defect in the major pathway of galactose metabolism.