Aging-Related Catatonia with Reversible Dopamine Transporter Dysfunction in Females with Depressive Symptoms: A Case Series.

OBJECTIVES: The authors describe five depressive patients with initially decreased striatal accumulation of dopamine transporter (DAT) single-photon emission computed tomography (SPECT), which improved in parallel with clinical symptoms. METHODS: Patients who exhibited decreased striatal accumulation and recovery of DATSPECT were identified among patients with the symptoms of depression. Their clinical and neuroimaging data were reviewed. RESULTS: Five patients were identified. All patients were presenile or senile women who presented with catatonia subsequent to symptoms of depression that remitted with treatment. DAT-SPECT showed a decreased striatal accumulation in all patients, which increased after treatment. Two patients had met the diagnostic criteria of probable dementia with Lewy bodies (DLB), but no longer did so after their symptoms improved. CONCLUSIONS: Reversible DAT dysfunction observed in this study suggests that reversible impairment of dopaminergic transmission in the striatum partly underlies catatonia. Careful consideration should be given to diagnosing DLB in patients with decreased DAT-SPECT accumulation, especially when catatonia is present.

DNA analysis of benign adult familial myoclonic epilepsy reveals associations between the pathogenic TTTCA repeat insertion in SAMD12 and the nonpathogenic TTTTA repeat expansion in TNRC6A.

Benign adult familial myoclonic epilepsy (BAFME) is an autosomal dominant disease characterized by adult-onset tremulous hand movement, myoclonus, and infrequent epileptic seizures. Recently, intronic expansion of unstable TTTCA/TTTTA pentanucleotide repeats in SAMD12, TNRC6A, or RAPGEF2 was identified as pathological mutations in Japanese BAFME pedigrees. To confirm these mutations, we performed a genetic analysis on 12 Japanese BAFME pedigrees. A total of 143 participants, including 43 familial patients, 5 suspected patients, 3 sporadic nonfamilial patients, 22 unaffected familial members, and 70 unrelated controls, were screened for expanded abnormal pentanucleotide repeats in SAMD12, TNRC6A, RAPGEF2, YEAT2, MARCH6, and STARD7. DNA samples were analyzed using Southern blotting, long-range polymerase chain reaction (PCR), repeat-primed PCR, and long-range PCR followed by Southern blotting. Of the 51 individuals with clinically diagnosed or suspected BAFME, 49 carried a SAMD12 allele with an expanded TTTCA/TTTTA pentanucleotide repeat. Genetic and clinical anticipation was observed. As in previous reports, the one patient with homozygous mutant alleles showed more severe symptoms than the heterozygous carriers. In addition, screening for expanded pentanucleotide repeats in TNRC6A revealed that the frequency of expanded TTTTA repeat alleles in the BAFME group was significantly higher than in the control group. All patients who were clinically diagnosed with BAFME, including those in the original family reported by Yasuda, carried abnormally expanded TTTCA/TTTTA repeat alleles of SAMD12. Patients with BAFME also frequently carried a TTTTA repeat expansion in TNRC6A, suggesting that there may be unknown factors in the ancestry of patients with BAFME that make pentanucleotide repeats unstable.

Sleep Disorders in Four Patients With Myotonic Dystrophy Type 1.

Sleep disturbances such as excessive daytime sleepiness, central and obstructive sleep apneas, restless legs syndrome, and rapid eye movement sleep dysregulation are prominent in patients with myotonic dystrophy type 1 (DM1). Mild intellectual deficits presented in many patients with DM1. In addition, psychosocial issues caused by neuropsychiatric symptoms are a clinical problem. We herein present the cases of four DM1 patients with sleep disturbances and neuropsychiatric symptoms in the preceding stage of clinically significant muscle symptoms. One of the cases exhibited a sleep disorder and neuropsychiatric symptoms before electromyography showed myotonic discharge, suggesting that careful follow-up is also important. Patients 1 and 2 were first referred to our department due to daytime sleepiness. Patients 3 and 4 were objectively suffering from daytime sleepiness of which they were not subjectively aware of. Patients 1, 3, and 4 obtained high apnea-hypopnea index (AHI) scores, which reflected central and/or obstructive apnea, whereas patient 2 had an AHI score of zero. The daytime cerebrospinal fluid (CSF) orexin levels of all patients ranged from the normal lower limit to low, although they were not as low as those observed in narcolepsy with typical cataplexy. Neuropsychological tests of patients 1 and 2 showed frontal lobe dysfunction. Patients 3 and 4 were diagnosed with mild intellectual disability and autism spectrum disorder, respectively. All patients exhibited indifference toward their own symptoms, which may have resulted from the cognitive decline caused by DM1. Based on family history and/or neurological findings such as myotonia, we suspected DM1 as the cause of their sleep disturbances. Molecular analysis using the triplet repeat-primed polymerase chain reaction (TP PCR) method and Southern blotting, which provided a genetic confirmation of the diagnosis of DM1, were performed. These clinical features of sleep disturbances were unrelated to the length of CTG repeats and are caused by unknown molecular mechanisms. Clinicians should take into account that multisystem involvement in DM1 is hugely variable, and thus, a disabling sleep disorder could overshadow muscle impairment in DM1 patients.

A patient with McLeod syndrome showing involvement of the central sensorimotor tracts for the legs.

BACKGROUND: McLeod syndrome is a rare X-linked recessive acanthocytosis associated with neurological manifestations including progressive chorea, cognitive impairment, psychiatric disturbances, seizures, and sensorimotor axonal polyneuropathy. However, no studies have investigated the functioning of central sensorimotor tracts in patients with McLeod syndrome. CASE PRESENTATION: A 66-year-old man had experienced slowly progressive chorea and gait disturbance due to lower limb muscle weakness since his early fifties. Blood examinations showed erythrocyte acanthocytosis and the reduction of Kell antigens in red blood cells. Brain magnetic resonance imaging showed atrophy of the bilateral caudate nuclei and putamen. The diagnosis of McLeod syndrome was confirmed by the presence of a mutation of the XK gene on the X chromosome. Somatosensory-evoked potential and transcranial magnetic stimulation studies demonstrated that the central sensory and motor conduction times were abnormally prolonged for the lower extremity but normal for the upper extremity. CONCLUSIONS: This is the first report of the involvement of the central sensorimotor tracts for the legs in a patient with McLeod syndrome. The clinical neurophysiological technique revealed the central sensorimotor tracts involvements clinically masked by neuropathy.

Novel pathogenic VPS13A gene mutations in Japanese patients with chorea-acanthocytosis.

OBJECTIVE: To identify mutations in vacuolar protein sorting 13A (VPS13A) for Japanese patients with suspected chorea-acanthocytosis (ChAc). METHODS: We performed a comprehensive mutation screen, including sequencing and copy number variation (CNV) analysis of the VPS13A gene, and chorein Western blotting of erythrocyte ghosts. As the results of the analysis, 17 patients were molecularly diagnosed with ChAc. In addition, we investigated the distribution of VPS13A gene mutations and clinical symptoms in a total of 39 molecularly diagnosed Japanese patients with ChAc, including 22 previously reported cases. RESULTS: We identified 11 novel pathogenic mutations, including 1 novel CNV. Excluding 5 patients with the unknown symptoms, 97.1% of patients displayed various neuropsychiatric symptoms or forms of cognitive dysfunction during the course of disease. The patients carrying the 2 major mutations representing over half of the mutations, exon 60-61 deletion and exon 37 c.4411C>T (R1471X), were localized in western Japan. CONCLUSIONS: We identified 13 different mutations in VPS13A, including 11 novel mutations, and verified the clinical manifestations in 39 Japanese patients with ChAc.

Novel pathogenic XK mutations in McLeod syndrome and interaction between XK protein and chorein.

OBJECTIVE: To identify XK pathologic mutations in 6 patients with suspected McLeod syndrome (MLS) and a possible interaction between the chorea-acanthocytosis (ChAc)- and MLS-responsible proteins: chorein and XK protein. METHODS: Erythrocyte membrane proteins from patients with suspected MLS and patients with ChAc, ChAc mutant carriers, and normal controls were analyzed by XK and chorein immunoblotting. We performed mutation analysis and XK immunoblotting to molecularly diagnose the patients with suspected MLS. Lysates of cultured cells were co-immunoprecipitated with anti-XK and anti-chorein antibodies. RESULTS: All suspected MLS cases were molecularly diagnosed with MLS, and novel mutations were identified. The average onset age was 46.8 ± 8 years, which was older than that of the patients with ChAc. The immunoblot analysis revealed remarkably reduced chorein immunoreactivity in all patients with MLS. The immunoprecipitation analysis indicated a direct or indirect chorein-XK interaction. CONCLUSIONS: In this study, XK pathogenic mutations were identified in all 6 MLS cases, including novel mutations. Chorein immunoreactions were significantly reduced in MLS erythrocyte membranes. In addition, we demonstrated a possible interaction between the chorein and XK protein via molecular analysis. The reduction in chorein expression is similar to that between Kell antigens and XK protein, although the chorein-XK interaction is a possibly noncovalent binding unlike the covalent Kell-XK complex. Our results suggest that reduced chorein levels following lack of XK protein are possibly associated with molecular pathogenesis in MLS.

Mouse model of chorea-acanthocytosis exhibits male infertility caused by impaired sperm motility as a result of ultrastructural morphological abnormalities in the mitochondrial sheath in the sperm midpiece.

Chorea-acanthocytosis (ChAc) is an autosomal recessive hereditary disease characterized by neurodegeneration in the striatum and acanthocytosis caused by loss-of-function mutations in the Vacuolar Protein Sorting 13 Homolog A (VPS13A) gene, which encodes chorein. We previously produced a ChAc-model mouse with a homozygous deletion of exons 60-61 in Vps13a, which corresponded to the human disease mutation. We found that male ChAc-model mice exhibited complete infertility as a result of severely diminished sperm motility. Immunocytochemical study revealed that chorein-like immunoreactivity is abundant only in the midpiece, mitochondria-rich region, of the sperm of wild type mice. They showed no significant differences from wild types in terms of the adenosine 5'-triphosphate (ATP) concentration of their sperm, sperm count, or sexual activity. Electron microscopy revealed abnormal ultrastructural morphology of the mitochondria in the midpiece of sperm from ChAc-model mice. These results suggest that chorein is essential in mouse sperm for the maintenance of ultrastructural mitochondrial morphology and sperm motility.

Chorein interacts with α-tubulin and histone deacetylase 6, and overexpression preserves cell viability during nutrient deprivation in human embryonic kidney 293 cells.

The autophagy pathway has recently been implicated in several neurodegenerative diseases. Recently, it was reported that chorein-depleted cells showed accumulation of autophagic markers and impaired autophagic flux. Here, we demonstrate that chorein overexpression preserves cell viability from starvation-induced cell death in human embryonic kidney 293 (HEK293) cells. Subsequent coimmunoprecipitation and reverse coimmunoprecipitation assays using extracts from chorein that stably overexpressed HEK293 cells revealed that chorein interacts with α-tubulin and histone deacetylase 6, a known α-tubulin deacetylater and central component of basal autophagy. Indeed, acetylated α-tubulin immunoreactivity was significantly decreased in chorein that stably overexpressed HEK293 cells. These results suggest that chorein/histone deacetylase 6/α-tubulin interactions may play an important role in starvation-induced cell stress, and their disruption may be one of the molecular pathogenic mechanisms of chorea-acanthocytosis.-Sasaki, N., Nakamura, M., Kodama, A., Urata, Y., Shiokawa, N., Hayashi, T., Sano, A. Chorein interacts with α-tubulin and histone deacetylase 6, and overexpression preserves cell viability during nutrient deprivation in human embryonic kidney 293 cells.