Donald H. Hunneman

X‐linked creatine deficiency syndrome: A novel mutation in creatine transporter gene SLC6A8

Among creatine deficiency syndromes, an X‐linked condition related to a defective creatine transport into the central nervous system has been described recently. Hallmarks of the disease are the absence of a creatine signal at brain spectroscopy, increased creatine levels in blood and urine, ineffectiveness of oral supplementation, and a mutation in the SLC6A8 (Online Mendelian Inheritance in Man [OMIM] 300036) creatine transporter gene. We report on a patient in whom a novel mutation (1221‐1223delTTC) was identified.

Identification of mutations in the ALD-gene of 20 families with adrenoleukodystrophy/adrenomyeloneuropathy.

Adrenoleukodystrophy (ALD), an X-linked inherited metabolic disorder, is the most frequent inborn peroxisomal disease. It leads to demyelination in the central and peripheral nervous system. Defective β-oxidation of saturated very long chain fatty acids (VLCFAs; C22:0–C26:0) in peroxisomes has been shown to lead to an accumulation of VLCFAs in leukoid areas of the central nervous system, peripheral nerves, adrenal gland, and blood. The ALD gene has been recently identified and encodes a 745-amino-acid protein. We screened patients with adrenoleukodystrophy/adrenomyeloneuropathy (ALD/AMN) from 20 kindreds for mutations in the ALD gene. Eleven missense and two nonsense mutations, five deletions, and one insertion were detected by direct sequencing of eight reverse transcribed fragments of the ALD-gene mRNA. Four mutations could be shown to be de novo. All mutations could be confirmed in carriers by sequencing genomic DNA. No correlation between the type of mutation and the severity of the phenotype could be observed. The mutations were not detected in the ALD gene of 30 healthy persons.

Reduced Sympathetic Metabolites in Urine of Obese Patients With Craniopharyngioma

Severe obesity is a major problem in patients suffering from craniopharyngioma (CP), a benign tumor located in pituitary and hypothalamic regions. In this study, the hypothesis that hypothalamic damage leads to a reduction in overall sympathetic tone was tested. Catecholamines, as well as their metabolites homovanillic acid (HVA) and vanillylmandelic acid (VMA), markers of catecholamine turnover, were measured in morning voided urine of 109 patients participating in a German pediatric CP study, and their physical activity was analyzed using a questionnaire. HVA and VMA results were compared with age-matched HVA and VMA in urine of patients proven to not have a catecholamine-secreting tumor. Patients with the most severe obesity displayed the lowest urine HVA and VMA values. Patients with hypothalamic CP had 3.2-fold higher BMI values (p < 0.0001), lower HVA (0.72-fold, p < 0.001), and VMA (0.84-fold, p < 0.01) values, and significantly lower activity scores than those without hypothalamic involvement, but their epinephrine- and norepinephrine/creatinine ratios were not significantly different, possibly due to low levels. The low HVA and VMA values suggest decreased sympathetic outflow contributing to reduced physical activity and severe obesity, especially in patients with a hypothalamic tumor. In further studies investigating treatment options for hypothalamic obesity, disturbed sympathetic tone should be considered.

Glyceroltrioleate/glyceroltrierucate therapy in 16 patients with X-chromosomal adrenoleukodystrophy/adrenomyeloneuropathy: Effect on clinical, biochemical and neurophysiological parameters

We have investigated the effect of glyceroltrioleate/glyceroltrierucate (GTO/GTE) therapy on X-chromosomal adrenoleukodystrophy in 16 patients with adrenoleukodystrophy (n=6), adrenomyeloneuropathy (n=3), Addison disease without neurological involvement (n=2), and neurologically and endocrinologically asymptomatic patients (n=5). Therapy was carried out for 19.4±10 months. All patients showed a normalization of C 26:0 plasma fatty acid concentrations. None of the seven neurologically asymptomatic patients developed neurological symptoms. Somatosensory evoked potentials of the tibialis nerve was the most sensitive electrophysiological parameter, showing a slight improvement in neurologically asymptomatic patients during therapy. In none of the patients with normal cranial MRI at start of therapy (n=6) has MRI deterioration been observed whilst on therapy. Follow up of the neurologically asymptomatic children supports the hypothesis that GTO/GTE therapy might prevent the development of neurological symptoms. Six of the nine neurologically symptomatic patients deteriorated to varying degrees whilst on therapy. MRI alterations have worsened in all patients with clinical deterioration.ConclusionGTO/GTE treatment should be initiated in all neurological asymptomatic boys before first neurological symptoms develop. To discover these patients very long-chain fatty acid determination should be performed in all family members at risk when adrenoleukodystrophy or adrenomyeloneuropathy is diagnosed.

Evaluation of the Preventive Effect of Glyceryl Trioleate-Trierucate (“Lorenzo’s Oil”) Therapy in X-Linked Adrenoleukodystrophy: Results of Two Concurrent Trials

X-linked adrenoleukodystrophy (X-ALD) is characterized by progressive neurological disability and primary adrenocortical insufficiency as a consequence of mutations in the ABCD1 gene that encodes a peroxisomal ATP binding cassette protein (Moseret al 2000a; Kempet al 2001) with a minimum incidence of 1:17,000 (Bezman et al. 2001). More than 400 different mutations have been identified (Kemp et al 2001). It is associated with the accumulation of saturated very long chain fatty acids, principally hexacosanoic (C26:0) and tetracosanoic acid (C24:0). High levels of these fatty acids are present in plasma (Moser et al 1999a). The neurologic manifestations show a wide range of severity. The childhood cerebral form (CCER) often leads to total disability and death by 10 years of age. Adrenomyeloneuropathy (AMN) presents as a paraparesis in young adults and progresses slowly (Powers et al 2000). Members of a family often have widely varying phenotypes. It is not possible to predict future course in asymptomatic young boys on the basis of mutation analysis, concentrations of VLCFA in plasma or cultured skin fibroblasts or phenotype in family members. The adrenal insufficiency in X-ALD can be treated successfully with steroid replacement therapy but apparently this does not alter the progression of the neurologic disease (Moser et al 2000a). Bone marrow transplantation (BMT) has been found to be of long-term benefit in boys and adolescents with cerebral involvement (Shapiro et al. 2000), but carries a high risk and is most effective when cerebral involvement is still mild.

Aromatic L-amino acid decarboxylase deficiency: An extrapyramidal movement disorder with oculogyric crises

Aromatic L-amino acid decarboxylase (AADC) deficiency results in an impaired synthesis of catecholamines and serotonin, and has been reported only in two middle eastern families. We report on a European family with an affected child. The child showed the characteristic clinical picture of an extrapyramidal movement disorder, oculogyric crises and vegetative symptoms seen in the three patients described previously. Treatment with a combination of the AADC cofactor pyridoxine, the monoamine oxidase B inhibitor selegiline and bromocriptine was started during the fifth year of life and showed only a moderate clinical improvement in contrast to patients who have been treated since the first year of life.

Facts and artefacts in mevalonic aciduria: development of a stable isotope dilution GCMS assay for mevalonic acid and its application to physiological fluids, tissue samples, prenatal diagnosis and carrier detection☆

A stable isotope dilution assay using D3-mevalonic acid was developed and applied to the study of mevalonic aciduria. The method also appears to be suitable for the evaluation of different therapeutic regimens in patients with hypercholesterolemia. Mevalonic acid was isolated by liquid partition chromatography and quantified as the underivatized lactone by means of ammonia chemical ionization selected ion monitoring capillary gas chromatography-mass spectrometry. In heterozygotes there was significantly greater urinary excretion of mevalonic acid, while the range of enzymatic activity of mevalonate kinase showed an overlap with that of controls. The analysis of amniotic fluids of two pregnancies at risk for mevalonic aciduria showed a 3277-fold elevation as compared to controls in the first case, diagnostic of an affected fetus, and a normal value in the second one. Mevalonic acid concentration was much increased in tissues of the affected and aborted fetus. Concentrations ranged from 840 to 1120 mumol/kg in various tissues and were as high as 1810 mumol/kg in brain. Concentrations in control fetal tissues were approximately 1 mumol/kg.

Sensitive in vivo assay of the phenylalanine hydroxylating system with a small intravenous dose of heptadeutero L-phenylalanine using high pressure liquid chromatography and capillary gas chromatography/mass fragmentography.

A method is described which allows the in vivo determination of the phenylalanine hydroxylating system in atypical and classical phenylketonuria. Phenylalanine-d7 is administered i.v. (0.030 g/kg body weight) within 10 min. Tyrosine-d6 in plasma is measured from 30 to 240 min post load by using a computerized capillary gas chromatography/mass fragmentography system. In two patients with hyperphenylalaninemia, the residual activity of the phenylalanine hydroxylating system was 15.7 and 3.7% of the normal, in two phenylketonurics 1.5 and 0.3% respectively. The in vivo figures correspond well to the in vitro assay of the residual activity of the phenylalanine hydroxylase in needle liver biopsy material.

Haematopoietic stem cell transplantation in 12 patients with cerebral X-linked adrenoleukodystrophy

Abstract. In an attempt to elucidate prognostic factors, the data on 12 boys who underwent haematopoietic stem cell transplantation (HSCT) for cerebral X-linked adrenoleukodystrophy were evaluated. Two further patients received HSCT but died from transplantation-related complications. The data included neurological examination, neuropsychological testing and magnetic resonance imaging (MRI). Follow-up after HSCT was up to 5.5 years. Six patients showed a moderate to severe clinical deterioration after HSCT including two who died within 6 months. In this group, a MRI severity score of 10 or higher before HSCT was associated with severe impairment and a score of more than 12 was followed by rapid deterioration and death after HSCT. The presence of neurological symptoms before HSCT also affected prognosis. Six patients showed no deterioration in neurological or neuropsychological assessment after HSCT. Conclusion: our data confirm that haematopoietic stem cell transplantation can stop the progress of demyelination when performed at a critical early stage of the disease. The prognosis in an individual patient for the clinical course after stem cell transplantation can in general be given based on the status before transplantation, although individual patients may show an unexpected course.

Mass fragmentographic determination of homovanillic and 4-hydroxy-3-methoxy mandelic acids in 50 μl plasma

Abstract A method is presented for the mass fragmentographic determination of homovanillic and 4-hydroxy-3-methoxy mandelic acids in 50 μl plasma or serum. The values found in normal, healthy adults agree well with previously published reports which required, however, much larger plasma volumes. The method uses a simple ethyl acetate extraction from acidified plasma and a one-step derivatisation with trifluoroethanol and pentafluoropropionic anhydride. The deuterium-labelled analogues are used as internal standards.