Newly identified milder phenotype of peroxisome biogenesis disorder caused by mutated PEX3 gene.

We identified the first patient with infantile Refsum disease (IRD), a milder phenotype of peroxisome biogenesis disorder (PBD) caused by a mutated PEX3, and investigated the clinical, molecular and cellular characterization in this patient. The patient presented psychomotor regression, late-onset leukodystrophy, peripheral neuropathy, hearing impairment, a renal cyst, and renal hypertension and survived until the age of 36. Furthermore, fibroblasts from the patient indicated a mosaic pattern of catalase-positive particles (peroxisomes) and numerous peroxisomal membrane structures. Molecular analysis was homozygous for the D347Y mutation and reduced gene expression of PEX3 which encodes a peroxisomal membrane protein, pex3p, involved in peroxisome assembly at the early stage of peroxisomal membrane vesicle formation, therefore, patients with a mutated PEX3 gene have been reported to have only a severe phenotype of Zellweger syndrome and no or less peroxisomal remnant membrane structure. This is not only a newly identified milder PBD caused by a mutated PEX3 gene but also the first report of a Japanese patient with IRD who had not been diagnosed until over 30years of age, which suggests there must be more variant PBD in patients with degenerative neurologic disorder, and to bring them to light is necessary.

[The effect of noninvasive positive pressure ventilation in children with severe motor and intellectual disabilities with respiratory insufficiency].

We investigated the clinical course of 20 children (persons) with severe motor and intellectual disabilities (SMID) who were treated with noninvasive positive pressure ventilation (NPPV) for respiratory insufficiency. NPPV was effective in 10 of 11 patients treated for acute respiratory failure, and in 7 of 9 patients treated for chronic respiratory failure. Twelve patients were treated with NPPV for more than one year. There were no complications associated with NPPV in any of the patients. NPPV improved ventilation impairment soon after ventilation was started, and avoided the need for the endtracheal intubation by adjusting airway management and the choice of mask in all but one of the patients with acute respiratory failure. NPPV in combination with wearing a chin strap was highly effective in patients with open state or upper airway obstruction. Five patients were successfully weaned off the ventilator soon after recovery from acute respiratory failure using NPPV, whereas 5 patients who continued NPPV during the chronic phase after recovery did not experience recurrent episodes of acute respiratory failure. We conclude that NPPV may be an effective treatment for SMID with respiratory insufficiency.

Acute neuropsychiatric disorders in adolescents and young adults with Down syndrome: Japanese case reports.

BACKGROUND: The aim of this study was to evaluate acute neuropsychiatric disorders in adolescents and young adults with Down syndrome. We report 13 Japanese adolescents or young adults with Down syndrome who developed acute neuropsychiatric disorders including withdrawal, depression, obsessive-compulsive behaviors, and occasional delusions or hallucinations. METHODS: THE FOLLOWING INFORMATION WAS COLLECTED FROM EACH PATIENT: age at onset of acute neuropsychiatric disorder, complications, signs and symptoms, personality traits before the onset of the acute neuropsychiatric disorder, prescribed medications with their respective doses and the response to treatment, and senile changes observed on magnetic resonance imaging or computed tomography. RESULTS: The mean age at onset of these disorders was 21.2 years. Brain imaging showed almost senile changes; patients responded well to low-dose psychotropic therapy. Patients had an onset at a young age and presented with treatable conditions, although the average age of the onset of Alzheimer's disease is generally over 40 years of age in patients with Down syndrome. CONCLUSION: These findings suggest that the pathology of acute neuropsychiatric disorder in patients with Down syndrome may be related to presenile changes; however, these disorders present features and a clinical course that is different from those presented in typical Alzheimer's disease with Down syndrome.