"Burnt-out" progressive multifocal leukoencephalopathy in idiopathic CD4+ lymphocytopenia.

Progressive multifocal leukoencephalopathy (PML) is a fatal disease caused by John Cunningham virus (JCV) infection; however, a growing number of PML patients now survive longer and achieve remission, largely due to the advent of combination antiretroviral therapy. Several reports have suggested that the pathology in such patients presents only chronic demyelination without characteristic cellular changes, being referred to as "burnt-out" PML. On the other hand, our knowledge of "burnt-out" PML is still substantially limited, especially in patients with non-human immunodeficiency virus infection. Here, we report a case of PML associated with idiopathic CD4+ lymphocytopenia (ICL) who presented with spontaneous remission and survived for 11 years after onset. Notably, postmortem examination revealed surprisingly broad "burnt-out" lesions lacking the classic histopathological findings. However, pathogenic JCV-specific DNA sequences was still present in the autopsied brain tissue. This case suggests that complete remission can be achieved with a persistent presence of JCV-specific pathogenic sequences, even after a catastrophic infection. Considering that there have been a few reported cases of PML with ICL with long survival, the long-term survival of our case may share a favorable immunological response that is unique to a subgroup of ICL.

Clinical and mutational spectrum of Japanese patients with recessive variants in SH3TC2.

SH3TC2, known as the causative gene of autosomal recessive demyelinating Charcot-Marie-Tooth type 4C (CMT4C), was also found linked to a mild mononeuropathy of the median nerve with an autosomal dominant inheritance pattern. Using DNA microarray, Illumina MiSeq, and Ion proton, we carried out gene panel sequencing among 1483 Japanese CMT patients, containing 397 patients with demyelinating CMT. From seven patients with demyelinating CMT, we identified eight recessive variants in the SH3TC2 gene, consisting of five novel (pathogenic/likely pathogenic) and three reported variants. Additionally, from two patients with axonal CMT, we detected a reported recessive variant, p.Arg77Trp, which was herein reclassified as variant with unknown significance. Of the seven CMT4C patients (six females and one male), 2/7 patients developed symptoms at their first decade, and 5/7 patients lost their ambulation around age 50. Scoliosis was observed from more than half (4/7) of these patients, whereas hearing loss is the most common symptom of central nervous system (6/7). No median nerve mononeuropathy was recorded from their family members. We identified recessive variants in SH3TC2 from 1.76% of demyelinating CMT patients. An uncommon gender difference was recognized and the wild spectrum of these variants suggests mutational diversity of SH3TC2 in Japan.

Identification of novel SNORD118 mutations in seven patients with leukoencephalopathy with brain calcifications and cysts.

BACKGROUND: Leukoencephalopathy with brain calcifications and cysts (LCC) is neuroradiologically characterized by leukoencephalopathy, intracranial calcification, and cysts. Coats plus syndrome is also characterized by the same neuroradiological findings together with defects in retinal vascular development. Indeed, LCC and Coats plus were originally considered to be the same clinical entity termed cerebroretinal microangiopathy with calcifications and cysts, but evidence suggests that they are genetically distinct. Mutations in CTS telomere maintenance complex component 1 (CTC1) and small nucleolar RNA, C/D box 118 (SNORD118) genes have been found to cause Coats plus and LCC, respectively. MATERIALS AND METHODS: Eight unrelated families with LCC were recruited. These patients typically showed major neuroradiological findings of LCC with no signs of extra-neurological manifestations such as retinal abnormality, gastrointestinal bleeding, or hematological abnormalities. SNORD118 was examined by Sanger sequencing in these families. RESULTS: Seven out of eight probands carry compound heterozygous mutations, suggesting that SNORD118 mutations are the major cause of LCC. We identified a total of eight mutation, including four that were novel. Some of the variants identified in this study present heterozygously in public databases with an extremely rare frequency (<0.1%). CONCLUSION: Biallelic SNORD118 mutations were exclusively found in most unrelated families with LCC.

Mutations in POLR3A and POLR3B encoding RNA Polymerase III subunits cause an autosomal-recessive hypomyelinating leukoencephalopathy.

Congenital hypomyelinating disorders are a heterogeneous group of inherited leukoencephalopathies characterized by abnormal myelin formation. We have recently reported a hypomyelinating syndrome characterized by diffuse cerebral hypomyelination with cerebellar atrophy and hypoplasia of the corpus callosum (HCAHC). We performed whole-exome sequencing of three unrelated individuals with HCAHC and identified compound heterozygous mutations in POLR3B in two individuals. The mutations include a nonsense mutation, a splice-site mutation, and two missense mutations at evolutionally conserved amino acids. Using reverse transcription-PCR and sequencing, we demonstrated that the splice-site mutation caused deletion of exon 18 from POLR3B mRNA and that the transcript harboring the nonsense mutation underwent nonsense-mediated mRNA decay. We also identified compound heterozygous missense mutations in POLR3A in the remaining individual. POLR3A and POLR3B encode the largest and second largest subunits of RNA Polymerase III (Pol III), RPC1 and RPC2, respectively. RPC1 and RPC2 together form the active center of the polymerase and contribute to the catalytic activity of the polymerase. Pol III is involved in the transcription of small noncoding RNAs, such as 5S ribosomal RNA and all transfer RNAs (tRNA). We hypothesize that perturbation of Pol III target transcription, especially of tRNAs, could be a common pathological mechanism underlying POLR3A and POLR3B mutations.

[A case of acute leukoencephalopathy induced by a combination of 5-fluorouracil and metronidazole].

We describe a 66-year-old woman who received folinic acid, leucovorin, fluorouracil and oxaliplatin for advanced rectal carcinoma. These drugs were initiated on day 1, and a pelvic abscess was identified on day 7. Piperacillin-tazobactam was initially administered, but was changed to ceftriaxone and metronidazole on day 14 on the basis of antimicrobial susceptibility testing. On the following day, the patient reported blindness, and MRI of the brain showed signal abnormalities in the splenium of the corpus callosum on DWI, suggestive of metronidazole encephalopathy. Although the total body exposure was 2 g, metronidazole was discontinued. The patient developed coma a few days later, and MRI of the brain on day 26 showed high signal intensity extensively involving the white matter in the cerebrum as well as the brainstem and cerebellum. She died 37 days after the initial administration of the chemotherapy. Pathological studies demonstrated decreased staining intensity in the myelin sheath and multiple vacuolar alterations, consistent with toxicity induced by metronidazole and fluorouracil. Care should be taken when administering a combination of these drugs, even if the total body exposure to each drug is limited.

[A case of primary central nervous system anaplastic lymphoma kinase positive anaplastic large cell lymphoma manifested as a unilateral pachymeningits].

There have been 23 reports of primary central nervous system anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma in the literature. Here we report the 24th case of a 40-year-old man who presented with occipital headache for one month. His contrast-enhanced brain MRI showed enhancement around the right temporal lobe, which suggested a diagnosis of hypertrophic pachymeningitis. He improved with steroid therapy. After discharge, however, he was readmitted with generalized convulsive seizures. Finally, he was diagnosed as primary central nervous system ALK-positive anaplastic large cell lymphoma by brain biopsy. Primary central nervous system lymphoma invading dura matter can rarely manifests as a unilateral pachymeningitis. Therefore, in case of pachymeningitis, we should pay attention to the possibility of infiltration of lymophoma with meticulous clinical follow-up.

[Mononeuritis multiplex due to thrombotic ischemia of primary antiphospholipid antibody syndrome without vasculitis: an autopsy case report].

The patient was a 78-year-old man. Three years before admission, he developed transient peripheral neuropathy and purpura, and at admission, he presented with livedo reticularis of both his lower extremities and with mononeuritis multiplex. Vasculitis was not observed, and antiphospholipid antibodies were detected. The nerve and skin biopsies revealed no inflammation; axonal degeneration accompanied by thrombi was found in his arterioles and venules. Based on these findings, he was diagnosed with ischemic peripheral neuropathy due to primary antiphospholipid syndrome. Administration of anticoagulant therapy resulted in an improvement in symptoms; however, two months later, a relapse occurred, and the patient contracted an infection while undergoing immunosuppressive therapy. The infection became fulminant, and the patient succumbed to multiple organ failure. The autopsy revealed a systemic arterial and venous embolism; however, no vasculitis was observed. Antiphospholipid syndrome, which is responsive to antithrombotic treatment, should be considered as a differential diagnosis of mononeuritis multiplex.

Different patterns of cerebellar abnormality and hypomyelination between POLR3A and POLR3B mutations.

BACKGROUND: Mutations of POLR3A and POLR3B have been reported to cause several allelic hypomyelinating disorders, including hypomyelination with hypogonadotropic hypogonadism and hypodontia (4H syndrome). PATIENTS AND METHODS: To clarify the difference in MRI between the two genotypes, we reviewed MRI in three patients with POLR3B mutations, and three with POLR3A mutations. RESULTS: Though small cerebellar hemispheres and vermis are common MRI findings with both types of mutations, MRI in patients with POLR3B mutations revealed smaller cerebellar structures, especially vermis, than those in POLR3A mutations. MRI also showed milder hypomyelination in patients with POLR3B mutations than those with POLR3A mutations, which might explain milder clinical manifestations. CONCLUSIONS: MRI findings are distinct between patients with POLR3A and 3B mutations, and can provide important clues for the diagnosis, as these patients sometimes have no clinical symptoms suggesting 4H syndrome.

[Small cerebellar vascular lesion can produce isolated conjugate deviation of the eyes].

The cerebellum has almost never been considered responsible for conjugate deviation of the eyes (CDE). A few cases of CDE caused by cerebellar lesions without the involvement of the brainstem have been reported, but the lesions were too large to evaluate their localization in the cerebellum. In this report, we describe 2 cases of isolated CDE caused by small cerebellar vascular lesions and a case of CDE and staggering gait that occurred following cerebellar infarction. We further describe cases of head rotation without CDE and those of vertigo without CDE or head rotation due to a similar small lesion. Case 1: A 73-year-old woman with rheumatism was brought to our department because of sudden-onset of difficulty in looking to the right. She was admitted 3 hours after onset; at admission she was alert and well-oriented and denied both vertigo and nausea. Neurologic examination revealed CDE to the left; however, no limb ataxia was detected. Diffusion-weighted MRI showed a small infarction in the white matter of the right PICA area near the vermis. Her CDE disappeared spontaneously within 2 days. Case 2: A 79-year-old man with hypertension exhibited CDE to the right without vertigo or ataxia following a small hemorrhage in the cerebellan area mentioned in Case 1. Case 3: A 65-year-old man with hypertension presented with CDE to the right and staggering gait after a small infarction in an area lateral to that mentioned above. The first 2 cases suggest that a small cerebellar vascular lesion can produce isolated CDE to the side contralateral to the lesion. The region responsible for CDE in these cases was located in the white matter of the PICA area near the vermis, although similar lesions in Cases 4 and 5 produced no CDE.