Schizophrenia and Hereditary Polyneuropathy: PMP22 Deletion as a Common Pathophysiological Link?

Background: Schizophrenic disorders are common and debilitating due to their symptoms, which can include delusions, hallucinations, and other negative symptoms. Organic forms can result from various cerebral disorders. In this paper, we discuss a potential association between schizophrenia and hereditary polyneuropathies (PNPs). Case presentation: We present the case of a 55-year-old female patient with chronically paranoid-hallucinatory schizophrenia, severe cognitive deficits since the age of 30, and comorbid repeated focal pressure neuropathies beginning at age 20. At the age of 35, genetic testing revealed a deletion on chromosome 17p12 covering the peripheral myelin protein 22 gene (PMP22), which led to the diagnosis of hereditary neuropathy with liability to pressure palsy (HNPP). Cerebral magnetic resonance imaging showed internal atrophy, magnetic resonance spectroscopy found alteration of the glutamate and myo-inositol levels in the anterior cingulate cortex, neuropsychological testing showed deficits in working memory and psychomotor speed, and electrophysiological testing detected signs of sensorimotor demyelinating PNP (accentuated in the legs). Conclusion: There may be an association between schizophrenia and HNPP. In observational studies, the deletion of interest (chromosome 17p12) was nearly 10 times more common in schizophreniform patients than in controls. This potential association could be pathophysiologically explained by the role of PMP22, which is mainly expressed in the peripheral nervous system. However, PMP22 mRNA and protein can also be found in the brain. PMP22 seems to play an important role in regulating cell growth and myelination, functions that are disturbed in schizophrenia. Such a connection obviously cannot be clarified on the basis of one case. Future studies should analyze whether patients with HNPP exhibit increased rates of psychotic disorders, and patients with schizophrenia and repeated focal pressure neuropathies should be examined for the PMP22 mutation. Alternatively, the co-occurrence of schizophrenia and HNPP could be coincidental.

Pathological Cerebrospinal Fluid Findings in Patients With Neuralgic Amyotrophy and Acute Hepatitis E Virus Infection.

There is growing evidence that hepatitis E virus (HEV) infection can present with extrahepatic manifestations including neurological disorders. Among these, neuralgic amyotrophy (NA) has been reported to occur in some industrialized countries. We investigated 35 patients with NA and a control group for markers of HEV infection. Acute HEV infection was found in NA patients only and was associated with an inflammatory response in the central nervous system. Shedding of HEV RNA into the cerebrospinal fluid and intrathecal production of anti-HEV immunoglobulin M occurred in 1 patient, suggesting that HEV is neurotropic.

Clinical phenotype and outcome of hepatitis E virus-associated neuralgic amyotrophy.

OBJECTIVE: To determine the clinical phenotype and outcome in hepatitis E virus-associated neuralgic amyotrophy (HEV-NA). METHODS: Cases of NA were identified in 11 centers from 7 European countries, with retrospective analysis of demographics, clinical/laboratory findings, and treatment and outcome. Cases of HEV-NA were compared with NA cases without evidence of HEV infection. RESULTS: Fifty-seven cases of HEV-NA and 61 NA cases without HEV were studied. Fifty-six of 57 HEV-NA cases were anti-HEV IgM positive; 53/57 were IgG positive. In 38 cases, HEV RNA was recovered from the serum and in 1 from the CSF (all genotype 3). Fifty-one of 57 HEV-NA cases were anicteric; median alanine aminotransferase 259 IU/L (range 12-2,961 IU/L); in 6 cases, liver function tests were normal. HEV-NA cases were more likely to have bilateral involvement (80.0% vs 8.6%, p < 0.001), damage outside the brachial plexus (58.5% vs 10.5%, p < 0.01), including phrenic nerve and lumbosacral plexus injury (25.0% vs 3.5%, p = 0.01, and 26.4% vs 7.0%, p = 0.001), reduced reflexes (p = 0.03), sensory symptoms (p = 0.04) with more extensive damage to the brachial plexus. There was no difference in outcome between the 2 groups at 12 months. CONCLUSIONS: Patients with HEV-NA are usually anicteric and have a distinct clinical phenotype, with predominately bilateral asymmetrical involvement of, and more extensive damage to, the brachial plexus. Involvement outside the brachial plexus is more common in HEV-NA. The relationship between HEV and NA is likely to be causal, but is easily overlooked. Patients presenting with NA should be tested for HEV, irrespective of liver function test results. Prospective treatment/outcome studies of HEV-NA are warranted.

Illness attribution of patients with medically unexplained physical symptoms in China.

The illness behavior of patients with medically unexplained physical symptoms (MUS) depends largely on what the patient believes to be the cause of the symptoms. Little data are available on the illness attributions of patients with MUS in China. This cross-sectional study investigated the illness attributions of 96 patients with MUS in the outpatient departments of Psychosomatic Medicine, biomedicine (Neurology, Gynecology), and Traditional Chinese Medicine in Shanghai. Patients completed the Illness Perception Questionnaire (IPQ) for illness attribution, the Screening Questionnaire for Somatoform Symptoms, the Hospital Anxiety and Depression Scale for emotional distress, and questionnaires on clinical and sociodemographic data. The physicians also filled out a questionnaire regarding the cause of the illness (IPQ). In contrast to previous research, both physicians and patients from all three areas of medicine most frequently reported "psychological attributions." The concordance between the physicians' and the patients' illness attributions was low. Emotional distress was an important predictor of psychological attributions. Further research should include large-scale studies among patients from different regions of China and qualitative studies to deepen our understanding of cultural influences on illness attribution.