Two adult galactosaemia females with normal ovarian function and identical GALT mutations (Q188R/R333G)

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.

Radiochemical assay of minute quantities of galactose-1-phosphate uridyltransferase activity in erythrocytes and leukocytes of galactosemia patients

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.

Biochemical and molecular studies of 132 patients with galactosemia

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.

Results of a survey of carrier women for the galactosemia gene

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.

Galactosemia: evaluation with MR imaging

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.

Verbal dyspraxia in treated galactosemia

Galactosemia is an inborn error of metabolism that causes life-threatening illness a few days after galactose-containing milk is fed to a newborn. Early treatment with a strict lactose-free diet results in rapid improvement, and, until recently, it was thought that the long-term prognosis in such infants was usually good. The speech characteristics of 24 patients treated for galactosemia were examined. Fifty-four percent had the specific speech disorder, verbal dyspraxia. This finding was not related to age at diagnosis, severity of symptoms in the newborn period, or to biochemical control. There may be, however, a relation between dyspraxia and diminished IQ scores observed in the group of patients with dyspraxia judged as "severe." The findings indicate the association of a specific and unusual speech defect with a specific and rare metabolic disorder.

Long-term prognosis in galactosaemia: results of a survey of 350 cases

An international survey of the long term results of treating galactosaemia has shown poor results. These do not seem to be related to any of the relevant variables studied, for example delayed diagnosis or poor dietary compliance.

Gonadal function and ovarian galactose metabolism in classic galactosemia

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.

Galactose metabolism in human ovarian tissue

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.

Deficit of uridine diphosphate galactose in galactosaemia

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.

Uridine nucleotide sugars in erythrocytes of patients with galactokinase deficiency

The levels of UDPglucose and UDPgalactose (UDPGal) have been measured in erythrocytes of seven patients with galactokinase deficiency. Normal levels of UDPGal were found in all patients with galactokinase deficiency (McKusick 23020). This is in contrast with reduced values of UDPGal found in patients with classical galactosaemia who have complete absence of galactose-1-phosphate uridyl transferase activity. It was demonstrated that patients with galactokinase deficiency had an incomplete enzyme block in erythrocytes by direct enzyme assay, by 14CO2 production from [1-14C]galactose, and by the appearance of labelled intermediates, notably galactose-1-phosphate and UDPhexose.

Methylmalonic and propionic acidemias: lipid profiles of normal and affected human skin fibroblasts incubated with [1-14C]propionate

Normal human skin fibroblasts and those from methylmalonic acidemia and propionic acidemia patients were grown in culture. Following incubation with [1-14C]propionate, the major lipid classes in the cells were separated by thin layer chromatography and isolated fractions analyzed by radio gas chromatography for the presence of odd-numbered long-chain fatty acids; the pattern of even-numbered long-chain fatty acids was obtained also. Normal fibroblasts incorporated a small percentage of propionate into odd-numbered fatty acids which were present in all lipids studied. The abnormal cells incorporated a larger amount while maintaining the characteristic ratios of odd-numbered fatty acids found in the normal line. Most of the radioactivity was associated with phospholipids which are the predominant constituents of cell membranes. A characteristic C15/C17 ratio was found for different phospholipids and the triglyceride fraction; pentadecanoic acid was the principal odd-numbered fatty acid utilized in the assembly of complex lipids. Compared to even-numbered long-chain fatty acids the absolute amount of odd-numbered fatty acids was low (1-2%), even in affected cells. An unusual polar lipid fraction was isolated in the course of the study. In the normal cell it contained several unlabeled eicosanoids which were missing from the same fraction of both affected cell lines.

Gonadal function in patients with galactosaemia

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.

Pyruvate carboxylase defect: metabolic studies on cultured skin fibroblasts

Oxidative studies using a number of radioactive carbon-labelled substrates on intact cultured skin fibroblasts from a patient with pyruvate carboxylase deficiency revealed dysfunction of the Krebs cycle. The suppression of CO2 production from aspartate but not glutamine strongly suggests that the defective function lies in the aspartate-malate shuttle. Furthermore, there is an unusual dependence on glutamine for the maintenance of growth of the patient's cells compared to normal cells. Glutamine could not be replaced by aspartate supplementation. A secondary defect resulting in accumulation of lipid material was also demonstrated in this study. It is speculated that the intracellular level of oxaloacetate may also be diminished in the patient's cells. Oxaloacetate is primarily generated by the carboxylation of pyruvate catalysed by pyruvate carboxylase.

Identification of a case of Y:18 translocation using a Y-specific repetitive DNA probe

We have used a recombinant DNA clone derived from the Y-specific 3.4-kb repeats for in situ chromosome hybridization and Southern blotting analysis to identify a case of de novo Y;18 translocation. The proband has a chromosome complement of 46,XY and a variant chromosome 18 with a Q-bright and C-positive short arm. The father has a normal male karyotype of 46,XY. The mother has a female karyotype of 46,XX and an unusually large Q-bright satellite on one chromosome 22. In situ hybridization with the 3.4-kb probe to the metaphase preparations of family members indicated that the additional Q-bright material in the proband's variant chromosome 18 derived from the Y chromosome of his father, and not from the variant chromosome 22 of his mother. On Southern hybridization, the proband had approximately twice the amount of 3.4-kb repeats per cell as his father. These observations suggest a de novo genetic rearrangement in the proband which probably occurred during the father's spermatogenesis.

Beta-glucuronidase deficiency. A heterogeneous mucopolysaccharidosis

We studied two cases of beta-glucuronidase deficiency. One patient's disease was present at birth and the other patient's disease appeared in early childhood. The symptoms observed in both patients, although of differing severity, included peculiar facies, cloudy cornea, hepatosplenomegaly, hernia, kyphosis, recurrent infections, short stature, and developmental delay, as well as increased excretion of urinary chondroitin sulfate A/C and decreased levels of beta-glucuronidase activity. We reviewed all of the reported cases and examined the biochemical and clinical heterogeneity observed in this disorder.

Partial ornithine transcarbamylase deficiency associated with recurrent hyperammonemia, lethargy and depressed sensorium

A 6-year-old boy presented with recurrent coma associated with hyperammonemia and infection is reported. A liver biopsy revealed decreased ornithine transcarbamylase (OTC) activity (16% of normal). The enzymatic abnormality in the child is supported by the finding of elevated orotic acid excretion in his mother following a protein load, compatible with an X-linked pattern of inheritance. Since initiation of a dietary arginine supplement, the child has not had recurrent episodes of hyperammonemia.

Immune functions in methylmalonicaciduria

A variety of phagocytic cell and lymphocyte assays were employed to evaluate the immune status of four patients with methylmalonicaciduria . One patient had a depressed absolute granulocyte count and two patients had depressed neutrophil and monocyte chemotactic responses. All subjects had normal neutrophil phagocytic and bactericidal activities. One patient had a decreased T-cell number; blastogenic responses to phytohaemagglutinin and pokeweed mitogen were normal in all subjects. B lymphocyte measurements were variably abnormal; two children had decreased B-cell numbers; two had marginally decreased IgG levels; a third had an undetectable rubella titre; and two had elevated serum IgE concentrations. In vitro exposure of normal cells to methylmalonic acid concentrations up to 50 mg/100 ml did not affect chemotactic or lymphoproliferative responses. In conclusion, although B-cell function may be affected, no consistent abnormality of lymphocyte or phagocytic cell functions could be attributed to the metabolic disorder.

Neonatal pyruvate carboxylase deficiency with renal tubular acidosis and cystinuria

This report concerns a patient with severe congenital lacticacidosis associated with proximal renal tubular acidosis and cystinuria. Enzyme studies with cultured skin fibroblasts obtained from the patient revealed zero pyruvate carboxylase activity, but propionyl-CoA carboxylase activity was normal. Administration of various vitamins in large amounts did not improve the clinical condition. In contrast, the patient began to thrive when her diet was supplemented with aspartic acid, asparagine, glutamic acid, and glutamine. The particular dietary treatment used and the biochemical findings merit consideration for management of future cases.

Hypergonadotropic hypogonadism in female patients 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.

Medical genetics for the otorhinolaryngologist

Genetic disorders involving the ear, nose and throat can be looked at in essentially the same way that one would view other genetic problems. It is important to differentiate genetic disorders from those due to environmental influences. This may be difficult on clinical grounds, since similar clinical features may be produced by different environmental factors or by different genes or groups of genes. When the cause of the disorder can be established, the risks involved in a family having further offspring usually can be determined reasonably readily. In the uncharacterized situations, empiric risk figures are employed. Abnormalities of genetic origin fall into one of three main groupings: chromosomal abnormalities, single gene mutations or polygenic inheritance. These situations are discussed and examples are given.

Developmental aspects of galactosemia from infancy to childhood

The developmental status of 60 galactosemic infants, their subsequent intellectual level, school status, visual-perceptual skills, and EEG results were analyzed. In addition, the intelligence of the parents and the unaffected siblings, as well as the educational and vocational status of the parents, were also investigated. The results reveal that the highest level of mental development was in the preschool age group. The lowest level, and still within normal limits, was in the school-age children. The overall findings are consistent with earlier observations that better progress is found in those individuals whose dietary control is instituted at the youngest age level.

Ocular findings in cytogenetic syndromes

Several cytogenetic syndromes are reviewed, and the salient ocular and facial abnormalities that might lead to a diagnosis are pointed out. Examples are given of mongoloid slant to the palpebral fissures, not only in Down's syndrome, but also in monosomy 9p, where, in addition, the triangular skull is almost diagnostic. Antimongoloid slant is found in trisomy 9p, where the eyes also have enophthalmos of monosomy 9p. Hypertelorism is another common finding in these syndromes; in monosomy 5p it is almost always present, although it occurs in other conditions as well, including trisomy 12p. The ring 22 syndrome has a distinguishing finding called "doe's eyes" because of the shape of the palpebral fissures. Trisomy 13 has numerous ocular findings as well as skull and facial involvements.

Regional mapping of the gene for human UDPGal 4-epimerase on chromosome 1 in mouse-human hybrids

Somatic cell hybrids between mouse and human cells containing two different reciprocal translocations involving human chromosome 1, 46,X,t(1;X)(q12;q26) and 47,XX,+21,t(1;17)(p32;p13), were studied for the expression of human uridine diphosphate galactose 4-epimerase (UDPGal 4-epimerase, E.C. 5.1.3.2) by starch-gel electrophoresis. Analysis of the hybrid clones for the expression of the enzyme and the presence of the translocation chromosome 1 has permitted the assignment of the gene for human UDPGal 4-epimerase to the pter yields p32 region of chromosome 1.

Biochemical studies of a human low-activity galactose-1-phosphate uridyl transferase variant

A low activity galactose-1-phosphate uridyl transferase (transferase) variant in a newborn infant has been demonstrated by biochemical studies in erythrocytes and cultured skin fibroblasts. The newborn infant was a galactosaemic suspect identified in a neonatal metabolic screening programme. On breast feeding, he did well without clinical symptoms of galactosaemia during the first 15 days of life. However, substantial amounts of erythrocyte galactose-1-phosphate and urinary galactitol corresponding to the levels in untreated galactosaemic patients, along with mild amino aciduria, were found. The transferase activity, as measured by a sensitive micro kinetic radioisotopic method, was about 7--10% of the normal. On starch gel electrophoresis, the enzyme from the haemolysate had similar mobility as the normal in Tris--glycine buffer, pH 8.8 and phosphate buffer, pH 7.0, but had a slower mobility than that of the normal in the histidine buffer, pH 7.8. The mobility difference was much clearer in a semipurified enzyme preparation. The transferase enzyme in the haemolysate appeared to be more heat labile.

Prenatal diagnosis of galactosemia

Prenatal diagnosis of disorders of galactose metabolism was done in one instance in a family with a known galactokinase deficiency and in six cases in five families at risk for galactosemia. The galactokinase activity in cultured amniotic cells was found to be normal, and the diagnosis was confirmed postnatally. In the six pregnancies at risk for galactosemia, four were considered to be unaffected and two to be affected. Of the latter, one was carried to term, and the erythrocyte transferase activity of the baby was shown to be absent. The other pregnancy was terminated, and examination of fetal tissues by biochemical studies confirmed the diagnosis. This experience substantiates the concept that prenatal diagnosis of disorders of galactose metabolism is feasible.

Radiographic features of fucosidosis

Fucosidosis is an uncommonly recognized lysosomal storage disease which presents with psychomotor deterioration and progressing in some cases to death. The roentgenographic findings in five boys from three families are described. Skeletal abnormalities of a dysostosis multiplex nature are present and though not diagnostic should direct the clinician to perform appropriate biochemical and tissue assay studies to establish the diagnosis.

Comparison of mental development in individuals with mosaic and trisomy 21 Down's syndrome

During the past 15 years about 350 children with Down's syndrome have been seen at Children's Hospital of Los Angeles for psychological evaluation along with medical visits and other laboratory tests. Among this group there were 25 mosaic Down's syndrome children identified by chromosome analyses. They were matched for sex and chronological age with 25 trisomy 21 subjects and compared on psychological tests. The mosaic group demonstrated significantly higher intellectual potential, better verbal facility, and less visual perceptual difficulties than the trisomy 21 group. Their behavioral adjustment and personality characterisitcs were similar to those observed in other types of Down's syndrome. Since present psychological assessment techniques do not permit reaching valid conclusions about the ultimate intellectual status in very young infants with Down's syndrome, physicians and other professionals need to be careful when recommending early placement outside the home based merely upon the diagnosis.

Differential fluorescence of sister chromatids with 4'-6-diamidino-2-phenylindole

Differential fluorescence of sister chromatids and sister chromatid exchanges (SCE) in chromosomes from human lymphocytes grown two replication cycles in medium containing 5-bromodeoxyuridine can be detected by fluorescence microscopy after staining with 4'-6-diamidino-2-phenylindole (DAPI). The DAPI fluorescence appears to be more stable than that of the dye 33258 Hoechst and may provide a more sensitive method for the detection of SCE.

The 9p- syndrome

Six patients (4 females and 2 males) with terminal deletion of the short arm of chromosome 9 distal to band p22 are described. The disorder constitutes a clinically identifiable syndrome consisting of mental retardation, sociable personality, trigonocephaly, mongoloid eyes, wide flat nasal bridge, anteverted nostrils, long upper lip, short neck, long digits mostly secondary to long middle phalanges, and predominance of whorls on fingers. The findings suggest that the clinical features are antithetical to the trisomy 9p syndrome. The deleted chromosome segment is relatively small and could be easily overlooked. It is hoped that this delineation of clinical features seen in 9,p- patients may help in focusing attention on the small deletion.

Biochemical and genetic studies of plasma and leukocyte alpha-L-fucosidase

Deficiency of alpha-L-fucosidase in plasma and leukocytes has been demonstrated in three patients affected with fucosidosis. The measurement of plasma fucosidase activity alone is of little diagnostic value. Several normal individuals were found to have extremely low plasma alpha-L-fucosidase activity, but normal activity in leukocyte preparations. The low plasma enzyme activity exhibited by clinically normal individuals appears to be an inherited characteristic. The plasma enzyme was found to be different from that of leukocytes in terms of electrophoretic mobility.