Multiple Carboxylase Deficiency Research Articles

Biotinidase deficiency: the possible role of biotinidase in the processing of dietary protein-bound biotin.

Biotinidase (EC 3.5.1.12) cleaves covalently-bound biotin from partially degraded carboxylases and from biocytin, thereby recycling biotin. We have recently demonstrated that the activity of biotinidase is deficient in serum from children with late-onset multiple carboxylase deficiency (Wolf et al., 1983a, b). Using a newly developed, sensitive radioassay, we have shown that biotinidase activity is also deficient in peripheral blood leukocytes and fibroblasts of affected patients (Wolf and McVoy, 1984). The enzyme activities in the parents of these children are intermediate between deficient and normal values. These findings indicate that the primary enzyme defect in late-onset multiple carboxylase deficiency is in biotinidase activity and that the disorder is inherited as an autosomal recessive trait. Children lacking biotinidase activity are unable to recycle biotin and depend on exogeneous biotin to prevent the clinical and biochemical features of biotin deficiency. Although previous reports have described’ impaired’ intestinal absorption of free biotin in patients with late-onset multiple carboxylase deficiency, the absorption of free biotin was found to be normal in one of these patients when loading studies were repeated while her tissues were not biotin-depleted. Moreover, this patient was found to be biotinidase deficient (Thoene and Wolf, 1983). Because there is considerable clinical variability in this disorder (Wolf et al., 1983c) and the concentrations of free and protein-bound biotin in foods are variable, biotinidase may also play a critical role in the processing of dietary protein-bound biotin.KeywordsPancreatic JuiceBiotinidase DeficiencyAutosomal Recessive TraitBiotinidase ActivityBiotin DeficiencyThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Complementation studies of isovaleric acidemia and glutaric aciduria type II using cultured skin fibroblasts.

Using cultured skin fibroblasts, we studied the heterogeneity of inborn errors of leucine metabolism such as isovaleric acidemia (IVA), glutaric aciduria type II (GA II), and multiple carboxylase deficiency (MC). We first developed a simple macromolecular-labeling test to measure the ability of cells to oxidize [1-14C]isovaleric acid in situ in culture. Cells from two different lines were fused using polyethylene glycol, and the ability of the heterokaryons to oxidize [1-14C]isovaleric acid was tested by the macromolecular-labeling test. The MC line complemented with all 10 IVA lines tested; heterokaryons showed 99 +/- 68% more activity than the unfused mixture of component cells. GA II/IVA heterokaryons exhibited poor growth, but when the culture remained confluent, the GA II cells complemented with all six IVA lines tested, showing a 71 +/- 41% increase in activity. The relatively large standard deviations are due to a few experiments in which significant enhancement of macromolecular-labeling test activity was not observed upon fusion, but significant complementation was clearly observed in repeats of the same combinations. These results are consistent with our previous findings, which indicated that the decreased ability of GA II cells to oxidize isovaleryl-CoA involves a defective electron-transporting system rather than a defective isovaleryl-CoA dehydrogenase. IVA/IVA heterokaryons showed no complementation in any combination tested, indicating no detectable heterogeneity in isovaleric acidemia. This finding indicates that the same gene is mutated in all IVA lines. Previous results indicated that this gene codes for isovaleryl-CoA dehydrogenase.

Stable isotope dilution analysis of 3-hydroxyisovaleric acid in amniotic fluid: contribution to the prenatal diagnosis of inherited disorders of leucine catabolism.

A quantitative assay for 3-hydroxyisovaleric acid in amniotic fluid was developed using D6-3-hydroxyisovaleric acid as an internal standard. 3-Hydroxyisovaleric acid was isolated by liquid partition chromatography and the amount determined by selected ion monitoring, ammonia chemical ionization gas chromatography-mass spectrometry of the trimethylsilyl derivatives. The concentration of 3-hydroxyisovaleric acid in ten normal amniotic fluid was 4.52 +/- 1.73 mumol/l. The level was elevated eight-fold in the amniotic fluid from a pregnancy resulting in the birth of a child with biotin-responsive multiple carboxylase deficiency. The stable isotope dilution assay of 3-hydroxyisovaleric acid in amniotic fluid is a rapid, sensitive and accurate method for the prenatal diagnosis of this disorder, and may be of value in the prenatal diagnosis of other inherited disorders of leucine catabolism.

Phenotypic variation in biotinidase deficiency

Biotinidase deficiency is the usual biochemical defect in biotin-responsive late-onset multiple carboxylase deficiency. We reviewed the clinical features of six patients with the enzyme deficiency and compared them with features described in the literature in children with late-onset MCD. In all of the reported probands, MCD was diagnosed because they had metabolic ketoacidosis and organic aciduria in addition to various neurologic and cutaneous symptoms, such as seizures, ataxia, skin rash, and alopecia. Although in several of our patients biotinidase deficiency was also diagnosed because they manifested a similar spectrum of findings, others never had ketoacidosis or organic aciduria. Thus the initial features of biotinidase deficiency usually include neurologic or cutaneous symptoms, whereas organic aciduria and MCD are delayed, secondary manifestations of the disease. These findings suggest that biotinidase deficiency should be considered in any infant or child with any of these neurologic or cutaneous findings, with or without ketoacidosis or organic aciduria. If the diagnosis cannot be excluded, such individuals should be given a therapeutic trial of pharmacologic doses of biotin.

Biotinidase deficiency: the enzymatic defect in late-onset multiple carboxylase deficiency

Late-onset multiple carboxylase deficiency is characterized clinically by skin rash, alopecia, seizures and ataxia and occasionally by candidiasis and developmental delay. Biochemically, these individuals exhibit findings consistent with a combined deficiency of the biotin-dependent carboxylases. We have found that the activity of the enzyme biotinidase is also deficient in the sera of five affected children (0 to 3% of mean control activity, 5.80 ± 0.89 nmol · min − · ml − serum), and believe that it represents the primary biochemical defect in this disease. Biotinidase catalyzes the removal of biotin from the ϵ-amino group of lysine, through which biotin is covalently bound to the four known human carboxylases, thereby regenerating biotin for reutilization. The deficient activity in our patients was not due to an inhibitor, particularly biotin. It is also not a consequence of feedback control in affected individuals under treatment with pharmacologie doses of biotin. The biotinidase activities of the parents of those children who were available for study were intermediate between deficient and normal values (46% to 65% of mean normal activity). Children lacking biotinidase activity are unable to recycle biotin, and are thus entirely dependent upon exogenous biotin to prevent deficiency. Our findings indicate that the primary biochemical defect in late-onset multiple carboxylase deficiency is in biotinidase activity which is inherited as an autosomal recessive trait.

Alopecia and periorificial dermatitis in biotin-responsive multiple carboxylase deficiency

Three siblings with infantile-onset biotin-responsive multiple carboxylase deficiency are described. Recognition of the characteristic dermatologic manifestations, alopecia and periorificial dermatitis, should result in early diagnosis and institution of potentially lifesaving therapy with biotin. Other metabolic disorders may present a similar clinical picture. Immunologic dysfunction and/or aberration in lipid or branched chain amino acid metabolism may be the common pathophysiologic link in some or all of these disorders.

Biotin dependent carboxylase activities in normal human and multicarboxylase deficient patient fibroblasts: relationship to the biotin content of the culture medium

Three mitochondrial carboxylase activities can be depleted in skin fibroblasts from patients with the neonatal form of multiple carboxylase deficiency when the biotin content of the culture medium is lowered to 25 nmol/l. On the other hand this depletion can be achieved in control fibroblasts or in fibroblasts from patients with the late onset form of the deficiency when avidin (50 U/l) is added to the culture medium. The kinetics of the carboxylase activity decrease are nevertheless identical for control and for both types of fibroblasts. After depletion, control and late onset form fibroblasts recover their carboxylase activities at the same rate, whereas fibroblasts with the neonatal form of deficiency need longer times or higher concentrations of biotin to restore their carboxylase activities. These results are consistent with previous hypotheses concerning the origin of both forms of the deficiency. In addition, this technique provides a convenient access to human apocarboxylases, i.e. substrates for in vitro holocarboxylase synthetase investigation.

Lactic acidosis in biotin-responsive multiple carboxylase deficiency caused by holocarboxylase synthetase deficiency of early and late onset

Two patients with biotin-responsive multiple carboxylase deficiency, both presenting with predominant lactic acidosis, are reported. One with disease of early neonatal onset had considerable acute neurologic and persistent dermatologic abnormalities. The other, with late juvenile-onset disease, had chronic neurologic abnormalities without dermatologic findings. Early-onset cases generally have been associated with holocarboxylase synthetase deficiency, whereas those of juvenile onset have been characterized as representing defects in intestinal biotin absorption. However, enzyme analyses of fibroblasts from both patients, grown in biotin-deficient medium, revealed markedly diminished activities of pyruvate, propionyl-CoA, and beta-methylcrotonyl-CoA carboxylases, and all three enzymes showed normal activities after growth in biotin-rich medium. Furthermore, lymphoblast enzyme analysis in the patient with disease of early onset had previously revealed a defect in holocarboxylase synthetase, and fibroblast complementation studies showed that both patients belong to the bio complementation group. These findings indicate that considerable clinical heterogeneity exists among patients with holocarboxylase synthetase deficiency, an observation which does not permit differentiation of the biochemical forms of multiple carboxylase deficiency on the basis of age at onset and clinical presentation.

Search for the biochemical basis of biotin dependent multiple carboxylase deficiencies: determination of biotin activation in cultured fibroblasts

Abstract The activation step of biotin into biotinyl-AMP, which precedes the fixation of the prosthetic group on the apocarboxylases, has been examined in cultured fibroblasts from patients with biotin-dependent multiple carboxylase deficiencies. Two kinds of patients were tested, those with a defective holocarboxylase synthetase activity and those with a low level of the vitamin in the plasma. In both cases, the activation step of biotin was found to be very close to normal values.

PRENATAL TREATMENT OF BIOTIN-RESPONSIVE MULTIPLE CARBOXYLASE DEFICIENCY

The prenatal diagnosis and prenatal treatment of a fetus with the neonatal-onset variant of biotin-responsive multiple carboxylase deficiency are described. Pre-amniocentesis maternal urinary organic-acid profiles were normal. Amniotic-fluid methylcitrate (17 weeks' gestation) was ten standard deviations above the control mean. Amniotic-fluid-cell propionyl CoA carboxylase, pyruvate carboxylase, and 3-methylcrotonyl CoA carboxylase activities were indistinguishable from activities in controls after cell growth in biotin-supplemented media. In contrast, growth in biotin-restricted media resulted in carboxylase activities significantly below control values. The fetus was considered to be affected, and the mother was begun on oral biotin at 231/2 weeks' gestation. The full-term baby girl exhibited no clinical or chemical aberrations during the first 4 days of life, before the start of postnatal biotin supplementation. Cord-blood biotin was 34 times the upper normal neonatal concentration. The diagnosis was confirmed by carboxylase assays on cultured skin fibroblasts obtained after birth; by slightly raised urinary organic-acid levels later in infancy; and by demonstration of· fibroblast holocarboxylase synthetase with an elevated K m(biotin) and a depressed V max. Growth and development of the baby have been normal to age 11/4 years on oral biotin. The prenatal diagnosis of neonatal-onset biotin-responsive multiple carboxylase deficiency can be made by means of enzymatic studies of amniotic-fluid cells. Amniotic-fluid methylcitrate should be a useful adjunct to enzymatic studies. Prenatal treatment was effective in our patient, and there was no apparent toxicity to mother or baby from biotin supplementation during the last 16 weeks of pregnancy.

Organic aciduria in neonatal multiple carboxylase deficiency

A Samoan patient and a Saudi-Arabian patient were found to have abnormalities in the pattern of organic acid metabolites characteristic of 3-methylcrotonylglycinuria, propionic acidaemia and lactic acidosis. Both patients died early in life. The metabolic pattern is diagnostic of multiple carboxylase deficiency and an enzymatic diagnosis was made in a subsequent affected sibling of the first patient. Deficiency of the three carboxylases suggests a primary defect in the metabolism of biotin which is required for their activity. The importance of the recognition of the clinical picture is highlighted by the fact that this lethal disease is readily treated with biotin. These patients have prominent skin lesions which can serve as alerting signs for the diagnosis.

Biochemical evidence for diverse etiologies in biotin-responsive multiple carboxylase deficiency.

Biotin-responsive multiple carboxylase deficiency can be categorized by clinical criteria into a neonatal-onset disorder and distinct syndrome of infantile onset. Pedigrees in each instance are consistent with autosomal recessive inheritance. For a neonatal-onset proband, the sensitivity to relative biotin deprivation and the rapid clinical response to biotin supplementation are reflected by in vitro studies. Specific activities of biotin-dependent pyruvate carboxylase, propionyl CoA carboxylase, and 1-methylcrotonyl CoA carboxylase are 0.8 to 16% of mean control values after growth of fibroblasts in intermediate and very low biotin concentrations. Following relative biotin depletion, pyruvate carboxylase activity returns to normal after only 14 hr of growth in biotin-supplemented medium. In contrast, carboxylase activities in fibroblasts of an infantile-onset proband remain normal at very low biotin concentrations, even when avidin is added to the growth medium. The clinical heterogeneity, taken together with the distinct responses of cultured skin fibroblasts to biotin deprivation in vitro, probably reflect fundamentally different etiologies for the two categories of biotin-responsive multiple carboxylase deficiency.

Prenatal administration of biotin in biotin responsive multiple carboxylase deficiency.

Biotin responsive multiple carboxylase deficiency was suspected in a third trimester conceptus on the basis of enzymatic confirmation in fibroblasts cultured from an earlier sibling who suffered a demise in the immediate neonatal period. Maternal urinary organic acid profile was normal throughout the final 4 wk of pregnancy. Oral administration of biotin, 10 mg/day to the mother resulted in a 100-fold increase in urinary biotin excretion within 7 days. Urinary biotin excretion over the subsequent 2 wk decreased steadily, suggesting either decreased maternal absorption or increased fetal sequestration. After the birth of nonidentical twins, cord blood and urinary organic acid profiles of the infants were normal. However, cord blood biotin concentration was 4 to 7-fold that of normal newborns. Subsequent enzymatic and genetic complementation studies utilizing cultured skin fibroblasts from the infants demonstrated one of them to be affected by the multiple carboxylase defect, although he was clinically and biochemically normal throughout the neonatal period. Thus, prenatal therapy of this inborn enzymatic defect can be safely and effectively accomplished by administration of pharmacologic biotin doses in the last month of pregnancy.

Neonatal Hyperammonemic Coma

Vomiting, lethargy, and coma in a neonate commonly bring to mind a differential diagnosis of sepsis, cardiopulmonary problems, or central nervous system disease. All too often, the possibility of an inborn error of metabolism is not considered. The failure to make such a diagnosis may result in either death or profound mental retardation in an affected infant. In this chapter we have reviewed the two principal causes of neonatal hyperammonemic coma: urea cycle enzymopathies and the organic acidemias. Effective therapy of UCE recently has been developed utilizing nitrogen restriction and alternative pathways of waste nitrogen excretion.9 Twenty-one of twenty-six patients treated in this fashion are alive at 7-52 months of age. Intellectual development has varied with the degree of hyperammonemia and the duration of coma (which is related to diagnostic delays). In the organic acidemias, results of therapy have been more variable. Those children with disorders that have been vitamin responsive (methylmalonic aciduria, propionic acidemia, and multiple carboxylase deficiency) generally have done well. Those dependent on dietary manipulation alone have done less well. Prenatal diagnosis is available in all the urea cycle enzymopathies and organic acidemias other than CPS and OTC deficiencies and glutaric acidemia, Type II. Heterozygote detection also is possible. Newborn screening is not generally available, nor would it be of much practical assistance in an infant who became comatose in the first few days of life.

Lymphoblasts and diagnosis of pyruvate carboxylase deficiency.

Pyruvate carboxylase activity was measured in phytohemagglutinin-transformed lymphocytes (i.e. lymphoblasts). Mean value +/- S.D. for 10 controls was 259 +/- 38 pmoles/min per mg protein. It was about 7 times higher than that of peripheral leukocytes and a half of cultured skin fibroblasts with similar techniques. Deficient pyruvate carboxylase activity less than 6 pmoles/min per mg protein was demonstrated in the lymphoblasts from a patient with biotin-dependent multiple carboxylase deficiency. It is suggested that lymphoblasts may allow more reliable and ready diagnosis of patients with pyruvate carboxylase deficiency.

Biotin‐responsive immunoregulatory dysfunction in multiple carboxylase deficiency

AbstractMultiple carboxylase deficiency could be associated with defects of the immunoregulatory system. A boy with documented multiple carboxylase deficiency was found to display a fatty acid and biotin‐responsive impairment of his lymphocyte suppressive activityin vitro. Furthermore, prostaglandin E2 (PGE2), a major product of unsaturated fatty acid elongation required forin vitro activation of the immunoregulatory system, was found to be very low in the patient's monocytes. Finally, PGE2 monocytic production responded well to biotin therapy. PGE2 deficiency could result from the combination of an essential fatty acid deficiency with an impaired elongation of unsaturated fatty acids possibly due to a defect of the biotin‐dependent acetyl‐CoA carboxylase reaction.

Biotin-responsive multiple carboxylase deficiency of infantile onset

B I O T I N R E S P O N S I V E C A R B O X Y E A S E D E F I C I E N C Y is being identified in a number of patients presenting with a characteristic pattern of lactic acidosis and accumulation of other organic acids. The increased urinary excretion of lactic acid, 3-OH propionic acid, methylcitric acid, 3-methylcrotonylglycine, and 3-OH isovaleric acid is consistent with deficient in vivo activity of at least three biotin-dependent carboxylases: pyruvate carboxylase (EC 6.4.111), propionyl-CoA carboxylase (EC 6.4.1.3), and 3-methylcrotonyl-CoA carboxylase (EC 6.4.1.4). These chemical findings can occur in children with quite disparate clinical courses. Some patients have variable symptoms beginning in the newborn period. 1 ' In addition, there is a more complex syndrome of infantile onset with ataxia, keratoconjunctivitis, al0pecia, and immunodeficiency? -'~ Herein we report our initial biochemical studies of a patient with the infantile-onset form, including studies of biotin levels in physiologic fluids.

The neonatal form of biotin-responsive multiple carboxylase deficiency

The neonatal form of biotin-responsive multiple carboxylase deficiency

Multiple Carboxylase Deficiency: Clinical and Biochemical Improvement Following Neonatal Biotin Treatment

Multiple carboxylase deficiency is characterized by deficient activities of three biotin-dependent enzymes, propionyl coenzyme A carboxylase, pyruvate carboxylase, and beta-methylcrotonyl coenzyme A carboxylase. A newborn infant was seen with metabolic ketoacidosis, hyperammonemia, organic aciduria, seizures, and coma. Multiple carboxylase deficiency was subsequently confirmed by enzyme activity determinations in his peripheral blood leukocytes and cultured skin fibroblasts. The infant's neurologic and metabolic status improved markedly within a few days of administration of pharmacologic doses of oral biotin. His EEG, which was distinctly abnormal, became normal; his extensive computed tomography scan changes resolved, with the exception of ventricular dilation, over the next two months. After two weeks of biotin treatment the excretion of abnormal organic acid metabolites was reduced and his carboxylase activities increased to the normal range. However, the activities of these enzymes increased only to 30% to 55% of normal in fibroblasts incubated in supplemental biotin. This partial correction of enzyme activity differs from that observed in other individuals with multiple carboxylase deficiency and suggests biochemical heterogeneity in this disorder. Prompt diagnosis and intervention can avert some of the pathologic complications of this biotin-responsive condition.

Biotin-Responsive Carboxylase Deficiency Associated with Subnormal Plasma and Urinary Biotin

AN increasing number of patients have been diagnosed as having biotin-responsive multiple carboxylase deficiency.1 2 3 4 5 6 7 8 This genetic disorder involves defects in the metabolism of biotin a...