Frequent misdiagnosis of adult polyglucosan body disease.

Adult polyglucosan body disease (APBD) is a rare glycogenosis manifesting progressive spastic paraparesis, sensorimotor polyneuropathy and neurogenic bladder. Misdiagnosis of APBD may lead to unnecessary investigations and to potentially harmful therapeutic interventions. To examine the frequency of misdiagnosis of APBD, we retrospectively reviewed the clinical data of 30 patients diagnosed between 1991 and 2013. Diagnosis was based on the combination of typical clinical and imaging findings, reduced glycogen branching enzyme activity, and the presence of p.Y326S GBE1 mutation. Initial symptoms started in the 5th-6th decade with bladder dysfunction (47 %), gait problems (33 %) or both. Diagnosis of APBD was delayed by 6.8 (±4.8) years. Consistent signs at diagnosis were spasticity in the legs (93 %), decreased or absent ankle reflexes (100 %), bilateral extensor plantar response (100 %) and distal sensory deficit (80 %). Nerve conduction study showed invariable sensorimotor polyneuropathy, and MRI demonstrated cervical spinal cord atrophy (100 %) and leukoencephalopathy (97 %). All 30 patients were initially misdiagnosed. Common misdiagnoses included cerebral small vessel disease (27 %), multiple sclerosis (17 %), amyotrophic lateral sclerosis (17 %) and peripheral neuropathies (20 %). Consequently, 27 % received inappropriate therapy. In addition, lower urinary tract symptoms in 60 % of men were attributed solely to prostatic disorders but did not respond to medical treatment or prostatectomy. These findings suggest that despite limited clinical variability, APBD is invariably misdiagnosed and patients are often mistreated. Physicians' unfamiliarity with the typical clinical and imaging features of APBD appears as the main reason for misdiagnosis.

Severe methylenetetrahydrofolate reductase deficiency: clinical clues to a potentially treatable cause of adult-onset hereditary spastic paraplegia.

IMPORTANCE: Hereditary spastic paraplegia is a highly heterogeneous group of neurogenetic disorders with pure and complicated clinical phenotypes. No treatment is available for these disorders. We identified 2 unrelated families, each with 2 siblings with severe methylenetetrahydrofolate reductase (MTHFR) deficiency manifesting a complicated form of adult-onset hereditary spastic paraparesis partially responsive to betaine therapy. OBSERVATIONS: Both pairs of siblings presented with a similar combination of progressive spastic paraparesis and polyneuropathy, variably associated with behavioral changes, cognitive impairment, psychosis, seizures, and leukoencephalopathy, beginning between the ages of 29 and 50 years. By the time of diagnosis a decade later, 3 patients were ambulatory and 1 was bedridden. Investigations have revealed severe hyperhomocysteinemia and hypomethioninemia, reduced fibroblast MTHFR enzymatic activity (18%-52% of control participants), and 3 novel pathogenic MTHFR mutations, 2 as compound heterozygotes in one family and 1 as a homozygous mutation in the other family. Treatment with betaine produced a rapid decline of homocysteine by 50% to 70% in all 4 patients and, over 9 to 15 years, improved the conditions of the 3 ambulatory patients. CONCLUSIONS AND RELEVANCE: Although severe MTHFR deficiency is a rare cause of complicated spastic paraparesis in adults, it should be considered in select patients because of the potential therapeutic benefit of betaine supplementation.

Frontotemporal dementia and parkinsonism with the P301S tau gene mutation in a Jewish family.

BACKGROUND: Frontotemporal dementia with parkinsonism linked to chromosome 17q21-22 (FTDP-17) is an autosomal dominant tauopathy manifested by a variable combination of personality changes, cognitive decline and hypokinetic-rigid movement disorder. Significant clinical and pathological heterogeneity of FTDP-17 is related in part to more than 20 different pathogenic mutations identified in the tau gene. Among others, the P301S mutation has been previously reported in three families of European and one of Japanese origin presenting with different clinical phenotypes. OBJECTIVES: To report a three-generation family of Jewish-Algerian origin with FTDP-17 due to the P301S tau mutation. METHODS: Clinical, neuropsychological and neuroimaging evaluation of 3 patients, tau genotyping, and pathological study of the proband. RESULTS: The 3 affected family members had a fairly stereotyped clinical course with early personality changes from their late 30s followed within a period of 1-2 years by a progressive cognitive and motor deterioration eventually leading to a state of akinetic mutism or death 3-5 years after the initial symptoms. The main clinical manifestations included severe dementia and hypokinetic-rigid movement disorder associated with supranuclear gaze impairment, pyramidal signs and frontal release signs. Brain imaging disclosed a variable degree of frontotemporal atrophy, ventriculomegaly and regional cerebral hypoperfusion or glucose hypometabolism. Frontal lobe biopsy in the proband revealed weak tau immunoreactivity in a few cortical neurons, in rare neurites and in some glial cells with no neurofibrillary tangles. Molecular DNA analysis identified a P301S mutation in exon 10 of the tau gene. CONCLUSIONS: The observed clinical features further expand the reported P301S phenotype and confirm a more aggressive course of the disease than in the other known tau mutations.