Clinical and metabolic correction of pompe disease by enzyme therapy in acid maltase-deficient quail.

Pompe disease is a fatal genetic muscle disorder caused by a deficiency of acid alpha-glucosidase (GAA), a glycogen degrading lysosomal enzyme. GAA-deficient (AMD) Japanese quails exhibit progressive myopathy and cannot lift their wings, fly, or right themselves from the supine position (flip test). Six 4-wk-old acid maltase-deficient quails, with the clinical symptoms listed, were intravenously injected with 14 or 4.2 mg/kg of precursor form of recombinant human GAA or buffer alone every 2-3 d for 18 d (seven injections). On day 18, both high dose-treated birds (14 mg/kg) scored positive flip tests and flapped their wings, and one bird flew up more than 100 cm. GAA activity increased in most of the tissues examined. In heart and liver, glycogen levels dropped to normal and histopathology was normal. In pectoralis muscle, morphology was essentially normal, except for increased glycogen granules. In sharp contrast, sham-treated quail muscle had markedly increased glycogen granules, multi-vesicular autophagosomes, and inter- and intrafascicular fatty infiltrations. Low dose-treated birds (4.2 mg/kg) improved less biochemically and histopathologically than high dose birds, indicating a dose-dependent response. Additional experiment with intermediate doses and extended treatment (four birds, 5.7-9 mg/kg for 45 d) halted the progression of the disease. Our data is the first to show that an exogenous protein can target to muscle and produce muscle improvement. These data also suggest enzyme replacement with recombinant human GAA is a promising therapy for human Pompe disease.

Acute hydrocephalus in nonketotic hyperglycinemia.

We present four patients with typical neonatal onset non-ketotic hyperglycinemia (NKH) who developed hydrocephalus requiring shunting in early infancy. Brain imaging revealed acute hydrocephalus, a megacisterna magna or posterior fossa cyst, pronounced atrophy of the white matter, and an extremely thin corpus callosum in all. The three older patients had profound developmental disabilities. This suggests that the development of hydrocephalus in NKH is an additional poor prognostic sign.

Cerebral defects and nephrogenic diabetes insipidus with the ARC syndrome: additional findings or a new syndrome (ARCC-NDI)?

We report on 4 children from 2 unrelated families who appear to have the lethal ARC syndrome (arthrogryposis, renal tubular dysfunction, and cholestasis) together with the additional findings of nephrogenic diabetes insipidus and cerebral anomalies, including deafness. With increased survival time in our patients, paucity of the intrahepatic bile ductules and cholestasis progressed to cirrhosis, growth was severely impaired, and severe mental retardation became apparent. No evidence was found for peroxisomal, chromosomal, or mitochondrial disorders. We propose to amend the ARC mnemonic to ARCC-NDI (A-Arthrogryposis, R-renal Fanconi, C-cerebral, C-cholestasis, NDI-nephrogenic diabetes insipidus) to name the major manifestations of this syndrome, several of which have not been appreciated.

Unbalanced translocation 46,XY,-15,+der(22)t(15;22)(q13;q11)pat: case report and review of the literature.

We present a boy with a rare unbalanced translocation 46,XY,-15,+der(22),t(15;22)(q13;q11) pat. Previous reports of similar chromosome findings mention only the Prader-Willi phenotype. At birth, his manifestations included severe hypotonia and lethargy, (typical of deletion of 15pter----q13); hypertelorism, down-slanting small palpebral fissures, preauricular tags, long philtrum (typical of duplication of 22pter----q11); severe laryngotracheomalacia, and proximal implantation of the thumb. In a review of the literature on chromosome abnormalities involving duplication of 22q11 the associated clinical phenotype consists of mild mental retardation, microcephaly, hypotonia, hypertelorism, down-slanting palpebral fissures, a long philtrum, cleft or highly arched palate, and ear abnormalities. Preauricular pits or tags are common. Cardiovascular defects, renal and genital problems and dislocated hips are frequently present. Anal atresia and colobomata are mainly seen in cat-eye syndrome, the phenotype associated with idic 22q11. Our findings indicate that patients with unbalanced t(15;22) can have manifestations of the dup 22q11, in addition to the previously reported Prader-Willi phenotype, even if the duplicated segment is small.

Molybdopterin synthase mutations in a mild case of molybdenum cofactor deficiency.

Molybdenum cofactor deficiency is a rare inborn error of metabolism with generally severe symptoms, most often including neonatal seizures and severe developmental delay. We describe a patient with an unusually mild form of the disease. Two mutations in MOCS2A (molybdenum cofactor synthesis enzyme 2A) were identified: a single base change, 16C > T, that predicts a Q6X substitution on one allele and a 19G > T transversion that predicts a valine to phenylalanine substitution, V7F, on the second. It is postulated that the milder clinical symptoms result from a low level of residual molybdopterin synthase activity derived from the 19G > T allele.

Hemangioma, supraumbilical midline raphé, and coarctation of the aorta with a right aortic arch: single causal entity?

Most congenital cutaneous hemangiomas are a sporadic occurrence. Hemangiomas have been found in association with coarctation of the aorta and a right aortic arch. A separate association has been noted of midline ventral defects with hemangiomas. We report on a patient with multiple hemangiomas, coarctation of the aorta and a right aortic arch, a superaumbilical midabdominal raphé and sternal cleft. Our patient represents an overlap between these two conditions. Review of the literature identified four additional patients with a similar combination of anomalies. The clinical overlap between these 5 patients suggests that they are variants of the same conditions and represent a spectrum of defects that includes hemangiomas, midline ventral defects, aortic arch abnormalities and brain malformation.

Fryns syndrome survivors and neurologic outcome.

Fryns syndrome is an autosomal recessive multiple congenital anomaly syndrome characterized by diaphragmatic hernia, unusual facies, and distal limb hypoplasia. It was first reported as a lethal condition. We report on a three-year-old survivor with Fryns syndrome, and provide a review on the outcome of other survivors. Patients who survive the neonatal period represent 14% of reported cases. Characteristics of survivors include less frequent diaphragmatic hernia and milder lung hypoplasia, absence of complex cardiac malformation, and neurologic impairment. Multiple central nervous system abnormalities have been reported in Fryns syndrome, including agenesis of the corpus callosum, Dandy-Walker abnormality, cerebellar heterotopias, cerebellar hypoplasia, enlarged ventricles, and hypoplasia of the olfactory bulbs. Our patient exhibited profound mental retardation. He had malformations of gyration and sulcation, particularly around the central sulcus, and hypoplastic optic tracts beyond the optic chiasm. Understanding of long-term outcome of survivors is important for counseling of families with Fryns syndrome. Careful brain examination is advised; however, a normal radiological brain examination does not preclude developmental delay. The spectrum of individual outcome and of associated anomalies indicates that individual evaluation, including imaging for structural brain malformation, is strongly advised.

Treatment of pyruvate carboxylase deficiency with high doses of citrate and aspartate.

A patient with severe pyruvate carboxylase deficiency presented at age 11 weeks with metabolic decompensation after routine immunization. She was comatose, had severe lactic acidemia (22 mM) and ketosis, low aspartate and glutamate, elevated citrulline and proline, and mild hyperammonemia. Head magnetic resonance imaging showed subdural hematomas and mild generalized brain atrophy. Biotin-unresponsive pyruvate carboxylase deficiency was diagnosed. To provide oxaloacetate, she was treated with high-dose citrate (7.5 mol/kg(-1)/day(-1)), aspartate (10 mmol/kg(-1)/day(-1)), and continuous drip feeding. Lactate and ketones diminished dramatically, and plasma amino acids normalized, except for arginine, which required supplementation. In the cerebrospinal fluid (CSF), glutamine remained low and lysine elevated, showing the treatment had not normalized brain chemistry. Metabolic decompensations, triggered by infections or fasting, diminished after the first year. They were characterized by severe lactic and ketoacidosis, hypernatremia, and a tendency to hypoglycemia. At age 3(1/2) years she has profound mental retardation, spasticity, and grand mal and myoclonic seizures only partially controlled by anticonvulsants. The new treatment regimen has helped maintain metabolic control, but the neurological outcome is still poor.

Benzoate therapy and carnitine deficiency in non-ketotic hyperglycinemia.

Five patients presenting with non-ketotic hyperglycinemia in the neonatal period were treated with sodium benzoate to normalize plasma glycine levels. This therapy resulted in seizure reduction and a marked increase in wakefulness. Plasma carnitine deficiency was noted in three of four patients tested, and benzoylcarnitine was identified in plasma, urine, and CSF. Treatment with L-carnitine normalized plasma free carnitine. L-carnitine showed a tendency to increase the glycine conjugation of benzoate. An episode of coma and increased seizures in one patient was associated with a toxic level of benzoate, probably due to insufficient mobilization of glycine for conjugation. High dose benzoate therapy improved the quality of life of surviving patients. Close monitoring of glycine, benzoate and carnitine levels is advised.

Mitochondrial myopathy with anemia, cardiomyopathy, and lactic acidosis: a distinct late onset mitochondrial disorder.

A 40-year-old woman presented with profound muscle weakness resulting in failure to wean from a ventilator and persistent lactic acidosis after having recovered from a pneumonia complicated by adult respiratory distress syndrome, myocardial infarction, renal failure and shock. She had a 28 year history of chronic anemia and exercise intolerance. Anemia and thrombocytopenia persisted after admission. Nonobstructive hypertrophic cardiomyopathy was present. A stroke-like episode occurred. A mitochondrial myopathy with deficiencies in complexes IV and II was demonstrated, but no DNA defect has yet been found. This patient represents a distinct clinical presentation of a mitochondrial disorder characterized by late onset mitochondrial myopathy, chronic anemia, cardiomyopathy, and lactic acidosis.

[Treatment of Pompe's disease with recombinant enzymes]. / Behandeling van de ziekte van Pompe met recombinant enzym.

Pompe disease is caused by the congenital deficiency of the lysosomal enzyme acid alpha-glucosidase. The accumulation of lysosomal glycogen results in a fatal myopathy and cardiomyopathy. We developed an enzyme replacement therapy based on recombinant human acid alpha-glucosidase enzyme targeted to the organs of interest by the presence of mannose-6-phosphate on this precursor enzyme and a manose-6-phosphate receptor present in muscle and heart. Using molecular techniques and following extensive selection, Chinese hamster ovary cells were developed that produced very large quantities of precursor human acid alpha-glucosidase in the culture medium. An improved method of purification of this precursor enzyme from tissue culture medium was developed. This purified precursor enzyme was taken up efficiently by patient's fibroblasts, and corrected with a single dose the lysosomal glycogen accumulation for one week. Finally, intravenous administration of the recombinant enzyme corrected the pathology and symptoms of an animal model of this disorder, the acid alpha-glucosidase deficient Japanese quail.

Ophthalmological findings in a patient with mucolipidosis III (pseudo-hurler polydystrophy). A case report.

Mucolipidosis III (Pseudo-Hurler Polydystrophy) is a rare autosomal recessively inherited Hurler-like disease. The ophthalmological findings in these patients include a triad of mild retinopathy, corneal clouding and hyperopic astigmatism. We present a patient with these ophthalmological characteristics.

Expanded motor and psychiatric phenotype in autosomal dominant Segawa syndrome due to GTP cyclohydrolase deficiency.

BACKGROUND: Segawa syndrome due to GTP cyclohydrolase deficiency is an autosomal dominant disorder with variable expression, that is clinically characterised by l-dopa responsive, diurnally fluctuating dystonia and parkinsonian symptoms. OBJECTIVE: To delineate the neurological and psychiatric phenotype in all affected individuals of three extended families. METHODS: GTP cyclohydrolase deficiency was documented by biochemical analyses, enzymatic measurements in fibroblasts, and molecular investigations. All affected individuals were examined neurologically, and psychiatric data were systematically reviewed. RESULTS: Eighteen affected patients from three families with proven GTP cyclohydrolase deficiency were identified. Eight patients presenting at less than 20 years of age had typical motor symptoms of dystonia with diurnal variation. Five family members had late-presenting mild dopa-responsive symptoms of rigidity, frequent falls, and tendonitis. Among mutation carriers older than 20 years of age, major depressive disorder, often recurrent, and obsessive-compulsive disorder were strikingly more frequent than observed in the general population. Patients responded well to medication increasing serotonergic neurotransmission and to l-dopa substitution. Sleep disorders including difficulty in sleep onset and maintenance, excessive sleepiness, and frequent disturbing nightmares were present in 55% of patients. CONCLUSION: Physicians should be aware of this expanded phenotype in affected members of families with GTP cyclohydrolase deficiency.

Benzoate treatment and the glycine index in nonketotic hyperglycinaemia.

High-dose benzoate treatment aimed at reducing plasma glycine levels to normal reduces seizures and increases wakefulness in patients with nonketotic hyperglycinaemia (NKH). Since benzoate metabolism is dependent on the available glycine pool, and since the glycine pool is variably affected by the deficiency in the glycine cleavage enzyme system, we examined the importance of interpatient variability in benzoate requirement. To correct for the dietary glycine contribution, the glycine index was introduced as the molar requirement of benzoate dose necessary to normalize plasma glycine levels and subtracting from that the dietary glycine intake, both corrected for weight. The glycine index varied between 3.62 and 4.87 mmol/kg per day in five patients with a poor neurodevelopmental outcome and between 0.92 and 1.90 mmol/kg per day in four patients with a better neurodevelopmental outcome, and was 2.54 mmol/kg per day in a single patient with an intermediate outcome. The glycine index was stable over time within each patient. Exceeding the balance by either increasing food glycine intake or decreasing the benzoate dose resulted in increased glycine levels. Exceeding the glycine tolerance by increasing benzoate resulted in elevated and toxic levels of benzoate. The glycine index is a stable, individually specific parameter in patients with NKH. It has clinical consequences for the dose of benzoate required and the role of dietary management. Through its correlation with neurodevelopmental outcome, the glycine index points to potential genetic factors that could contribute to the psychomotor retardation in NKH.

Expression of catalytically active human multifunctional glycogen-debranching enzyme and lysosomal acid alpha-glucosidase in insect cells.

Glycogen debranching enzyme and acid alpha-glucosdase are responsible for glycogen degradation in human. The formal enzyme is a multifunctional enzyme with two independent catalytic activities occurring on a single polypeptide, while the latter is a lysosomal enzyme which matures through extensive glycosylation and phosphorylation and proteolytic processing. Deficiency of glycogen debranching enzyme and acid alpha-glucosidase cause glycogen storage disease type III and II, respectively. Baculovirus/insect expression system was used to produce both GDE and GAA. Both enzymes were found to be catalytically and antigenically active. The majority of recombinant GDE is present in the medium (70%). Uptake experiment indicated that GAA produced in the insect cells could not be absorbed into the GSD type II patient fibroblasts through mannose-6-phosphate receptor mediated endocytosis. Uptake experiment combined with immunoblot analysis indicated there are differences in the posttranslational modification and processing between insect cells and mammalian cells.

Rapid diagnosis of MCAD deficiency: quantitative analysis of octanoylcarnitine and other acylcarnitines in newborn blood spots by tandem mass spectrometry.

We report the application of tandem mass spectrometry to prospective newborn screening for medium-chain acyl-CoA dehydrogenase (MCAD) deficiency. MCAD deficiency is diagnosed from dried blood spots on filter paper cards from newborns on the basis of the increase of medium chain length acylcarnitines identified by isotope dilution mass spectrometry methods. A robust and accurate semiautomated method for the analysis of medium chain length acylcarnitines as their butyl esters was developed and validated. Quantitative data from the analyses of 113 randomly collected filter paper blood spots from healthy newborns showed low concentrations of medium chain length acylcarnitines such as octanoylcarnitine. The maximum concentration of octanoylcarnitine was 0.22 mumol/L, with the majority being at or below the detection limit. In all 16 blood spots from newborns with confirmed MCAD deficiency, octanoylcarnitine was highly increased [median 8.4 mumol/L (range 3.1-28.3 mumol/L)], allowing easy detection. The concentration of octanoylcarnitine was significantly higher in these 16 newborns (< 3 days of age) than in 16 older patients (ages 8 days to 7 years) with MCAD deficiency (median 1.57 mumol/L, range 0.33-4.4). The combined experience of prospective newborn screening in Pennsylvania and North Carolina has shown a disease frequency for MCAD deficiency of 1 in 17,706. No false-positive and no known false-negative results have been found. A validated method now exists for prospective newborn screening for MCAD deficiency.

Acylcarnitines in amniotic fluid: application to the prenatal diagnosis of propionic acidaemia.

Acylcarnitines were assayed in amniotic fluid by isotope dilution tandem mass spectrometry. Control values for propionylcarnitine, C4 and C5 acylcarnitines were established. Propionylcarnitine was elevated by a factor of 5 relative to controls in the amniotic fluid of three pregnancies affected with propionic acidaemia. This may provide a convenient new method for prenatal diagnosis of propionic acidaemia. One pregnancy at risk for propionic acidaemia but unaffected according to methylcitrate analysis had an intermediate level of propionylcarnitine, indicating the need for further studies to determine the range of concentration in probable heterozygotes.

Neuroleptic malignant syndrome in juvenile neuronal ceroid lipofuscinosis associated with low-dose risperidone therapy.

We present a patient with juvenile neuronal ceroid lipofuscinosis who developed a neuroleptic malignant syndrome when treated for hallucinations with a very low dose of risperidone, an atypical neuroleptic medication with usually few extrapyramidal side-effects. The loss of dopaminergic neurons in this condition may make these patients more vulnerable to this severe adverse effect.

Liquid chromatographic assay for a glucose tetrasaccharide, a putative biomarker for the diagnosis of Pompe disease.

A HPLC method associated with butyl-p-aminobenzoate derivatization has been developed for the analysis of a tetraglucose oligomer, Glcalpha1-6Glcalpha1-4Glcalpha1-4Glc, designated Glc(4), in biological fluids. This tetraglucose, normally excreted in the urine, has previously been shown to be elevated in a number of pathological conditions including Pompe disease (glycogen storage disease type II), which is caused by a deficiency of the lysosomal enzyme acid alpha-glucosidase. Concentrations of Glc(4) in both urine and plasma were established for the age ranges of <1, 1-5, 6-10, 11-20, and >20 years, both in normal individuals and in a cohort of 21 patients with enzymatically confirmed Pompe disease. The Glc(4) concentration decreased with age in both groups, but all the patients had elevated Glc(4) levels compared with age-matched controls. Electrospray tandem mass spectrometry was employed to establish the homogeneity of the HPLC peak for Glc(4) and to investigate the identity of other unusual oligosaccharides excreted in patient urine. Our results demonstrate that this method is suitable for application in clinical laboratories to help establish the diagnosis of Pompe disease.

Acute pancreatitis in an infant with lactic acidosis and a mutation at nucleotide 3243 in the mitochondrial DNA tRNALeu(UUR) gene.

UNLABELLED: The A to G point mutation at position 3243 of the mitochondrial DNA tRNALeu(UUR) gene is commonly found in patients with the syndrome of mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS). A male patient was referred at 7 months with failure to thrive, developmental delay, microcephaly and hypotonia since age 2 months. He had developed lactic acidosis and increasingly frequent seizures since age 5 months. The patient was admitted at 15 months with pleural and pericardial effusions, which resolved. Three weeks later he developed evidence of pancreatitis with hyperglycemia, sudden profound increase in lactic acidosis and increased serum lipase. He died unexpectedly the next day of cardiorespiratory collapse following an acute gastro-intestinal hemorrhage. Analysis of mitochondrial DNA (mtDNA) in muscle showed heteroplasmy for the mutation MTTL1*MELAS3243G (> 95%). Infants with this mutation commonly present with failure to thrive, significant developmental delay, and hypotonia, while stroke-like episodes occur later in survivors. They usually have lactic acidosis and a high percentage of mutant mtDNA in muscle. CONCLUSION: Respiratory chain disorders including the mtDNA MTTL1*MELAS3243G mutation should be suspected in infants with this systemic and neurologic presentation. Pancreatic dysfunction, both acute and chronic, needs to be added to the list of symptoms of disorders of the respiratory chain.