Incidence of peroxisomal disorders in Japan

Gas chromatography/mass spectrometry analysis of very long chain fatty acids, docosahexaenoic acid, phytanic acid and plasmalogen for the screening of peroxisomal disorders

Very long chain fatty acids (VLCFAs) and docosahexaenoic acid (DHA), phytanic acid, and plasmalogens are usually measured individually. A novel method for the screening of peroxisomal disorders, using gas chromatography/mass spectrometry (GC/MS), was developed. Saturated and unsaturated fatty acids, including VLCFAs and DHA, phytanic acid, and plasmalogen were detected by a selected ion monitoring-electron impact method, using 100 microl of serum or plasma. Methyl-esterification and extraction could be done in one tube, and data were obtained within 4 h. All patients with Zellweger syndrome (ZS), X-linked adrenoleukodystrophy (ALD), isolated deficiency of peroxisomal beta-oxidation enzyme, and most ALD carriers showed increased VLCFA ratios, including C24:0/C22:0, C25:0/C22:0 and C26:0/C22:0. The ratio of DHA to palmitic acid (C16:0) and plasmalogen (measured as hexadecanal dimethyl acetal) to C16:0 in ZS patients was significantly lower than for the controls (P<0.001 for healthy high school students, P<0.05 for infants with other disorders). Plasmalogen was also decreased in patients with isolated deficiency of plasmalogen biosynthesis. Two of eight patients with ZS, two of four with RCDP, and all of three classical Refsum patients showed increased levels of phytanic acid. This method will simplify the screening for peroxisomal disorders.

Peroxisomal acyl CoA oxidase deficiency

Three Japanese patients with peroxisomal acyl coenzyme A oxidase deficiency who manifested psychomotor retardation and regression during the late infantile period showed characteristic patterns of demyelination in the ponto- medullary corticospinal tracts and in the cerebellar and cerebral white matter. Molecular investigations revealed 2 novel missense mutations, M278V and G178C.

Urinary organic acids in peroxisomal disorders: a simple screening method

Using GC-MS, we studied urinary organic acids in 20 Japanese patients with peroxisomal disorders, including Zellweger syndrome (ZS), neonatal adrenoleukodystrophy, and single deficiency of peroxisomal beta-oxidation enzymes. Non-ketotic dicarboxylic aciduria with elevated sebacate/adipate molar ratio was observed in 19 of the 20 patients. Elevation of 2-hydroxysebacate and epoxydicarboxylic acids were seen in 13 and 18, respectively. Tyrosyluria was remarkable in all patients. In two ZS patients, we tracked the time course from birth to infancy, and all the above stated findings were detected, except for one sample. Urinary organic acid analysis is indeed useful for screening subjects with peroxisomal disorders.

The clinical course of childhood and adolescent adrenoleukodystrophy before and after Lorenzo's oil

The clinical course of Japanese patients with childhood and adolescent adrenoleukodystrophy (ALD) who were treated with Lorenzo's oil after the progression of early symptoms was investigated by Kaplan-Meier analyses. Many of the early symptoms, including visual, personality, hearing, mental and speech disturbances, had already appeared when the oil therapy was started. These early symptoms appeared significantly faster than bed-ridden state or dysphagia (P<0.01). Gait disturbance appeared faster than bed-ridden state and dysphagia (P<0.05), and tended to appear later than the early symptoms. These results would reflect the early natural course of childhood and adolescent ALD before treatment, and provide a basis for the evaluation of therapeutic trials for ALD.

Bone marrow transplantation for the treatment of X-linked adrenoleukodystrophy

The effects of bone marrow transplantation (BMT) in X-linked childhood adrenoleukodystrophy (ALD) are described in four Japanese patients. Two older patients, 10-year-old boys with IQ 60 and difficulty in school, had favourable results. IQ levels and MRI findings were generally maintained after BMT. One patient showed improvement of gait disturbance. They have both attended ordinary schools after BMT, although a learning disorder persists. On the other hand, two other younger patients with a rapid course and indeterminate IQ at BMT showed deterioration of neurological functions. Indication for BMT seems to be a maintained IQ level, preferably higher than 80, since it seems to be difficult to normalize IQ level after BMT. Younger patients have higher risk of developing a rapidly progressive form of the disease. Identification of presymptomatic boys, and serial and careful follow-up by neuropsychological and neuroradiological studies, are essential prerequisites to successful BMT in X-ALD.

Trial of docosahexaenoic acid supplementation on a Japanese patient with a peroxisome biogenesis defect

A female Japanese patient diagnosed with peroxisome biogenesis defect (PBD), who had hypotonia and craniofacial dysmorphism, was given supplementation of docosahexaenoic acid (DHA). Accumulation of very long chain fatty acids was revealed, and a diagnosis of PBD was made at 2 months of age because of the absence of peroxisomes, a defect in peroxisomal beta-oxidation enzymes and a decreased level of DHA in the erythrocytes. Supplementation of DHA was introduced at 3 months of age. For the first several months, psychomotor development was fairly good. The patient could laugh, brush off a blanket and play with toys at 6 months of age. However, neurological regression and convulsions occurred after 7 months of age. After recurrent respiratory infections and disturbance of the circadian rhythm, the patient died of liver failure and disseminated intravascular coagulopathy at 20 months of age. DHA may have a favorable effect on the early development of patients with PBD, but neurological deterioration cannot be prevented. Patients with a milder phenotype would be better candidates for DHA supplementation.