Noncanonical splice-site variant in peripheral myelin protein 22 gene (PMP22) in a patient with hereditary neuropathy with liability to pressure palsies.

AIM: Hereditary neuropathy with liability to pressure palsies (HNPP) is a peripheral neuropathy with autosomal dominant inheritance. Diagnosis can be made from the characteristic abnormalities determined by nerve conduction studies (NCS), including subclinical deficits at physiological compression sites. Heterozygous deletion of the chromosome 17p11.2-p12 region including the peripheral myelin protein 22 gene (PMP22) is the cause in the majority of cases. However, the loss of function of PMP22 due to frameshift-causing insertion/deletion, missense, nonsense, or splice-site disrupting variants cause HNPP in some patients. We report a case of a patient diagnosed with HNPP on the basis of clinical features and the results of NCS. No deletions of PMP22 were detected by fluorescence in situ hybridization. METHODS: We performed direct nucleotide sequence analysis and identified a heterozygous variant, c.78 + 3G > T, in PMP22. Since this variant is located outside the canonical splice site at the exon 2-intron 2 junction, we investigated whether the variant causes aberrant splicing and leads to the skipping of exon 2 of PMP22 by in vitro minigene splicing assay. RESULTS: We demonstrated that the c.78 + 3G > T variant causes the skipping of exon 2 and leads to loss of function of the mutant allele. CONCLUSION: Searching for sequence variants located outside the canonical splice sites should also be considered even when deletion of PMP22 is not found in a patient with a clinical diagnosis suggesting HNPP.

Weak shoulder and arm sparing signs in amyotrophic lateral sclerosis.

INTRODUCTION/AIMS: Various signs of selective involvement have been reported in amyotrophic lateral sclerosis (ALS). In this study, we describe two new signs, "weak shoulder" and "arm sparing" signs. METHODS: Subjects were retrospectively identified from our electrodiagnosis database. Medical Research Council scores of relevant muscles were evaluated. Weak shoulder was defined as the deltoid (Del) muscle being weaker than the biceps brachii (BB)/triceps brachii (TB) muscles; that is, Del was weaker than either or both of the muscles and no stronger than either. Arm sparing was defined as both Del and the first dorsal interosseous (FDI) being weaker than BB/TB. Sensitivities of these signs were compared with other signs of selective involvement. The specificities of these signs were investigated in patients with cervical spondylotic amyotrophy (CSA) and multifocal motor neuropathy (MMN). RESULTS: We reviewed 130 patients with ALS, 64 patients with CSA, and 16 patients with MMN. The weak shoulder and the arm sparing signs were observed in 73% and 55% of patients with ALS, 44% and 2% of patients with CSA (93% and 0% of patients with proximal CSA), respectively, and no patients with MMN. The sensitivity of the weak shoulder was higher than with conventional signs, whereas that of the arm sparing sign showed no difference. DISCUSSION: The weak shoulder sign was highly sensitive in ALS, and was specific when compared with MMN. The arm sparing sign was highly specific for ALS. These two new signs are promising as clinical clues in the diagnosis of ALS.

Guillain-Barré Syndrome Mimicking Lumbar Spinal Stenosis with Segmental Weakness in L5-S1 Myotomes: Two Case Reports.

We herein report two cases of Guillain-Barré syndrome (GBS) mimicking lumbar spinal stenosis (LSS). Both cases were initially diagnosed as LSS based on prominent segmental weakness in the L5 and S1 myotomes and coexisting LSS on magnetic resonance imaging. However, neurological and electrophysiological examinations revealed abnormalities that extended to the upper extremities, although slight, prompting us to suspect GBS. Subsequently, serum antiganglioside antibodies and remarkable responsiveness to intravenous immunoglobulin therapy confirmed GBS. We suspect that the focal blood-nerve barrier disruption due to preexisting LSS might have contributed to the segmental weakness in this atypical GBS case.

The influence of right-left error in the placement of the Cc electrode in tibial nerve somatosensory evoked potentials (SEPs).

OBJECTIVE: At our laboratory, we routinely record tibial nerve somatosensory evoked potentials (SEPs) using 5 channels including the second cervical vertebra (C2S)-contralateral central area (Cc) and Cz' (2 cm posterior to Cz)-Cc derivations. In a man with lumbar spondylotic myelopathy, symptoms improved after surgery, although the N21-P38 interval was markedly prolonged in comparison with that before surgery. We presumed that the Cc electrode was actually placed on the ipsilateral central area (Ci) at the second examination. Inspired by this episode, we investigated the influence of the right-left error in the placement of the Cc electrode. METHODS: Subjects were 20 healthy volunteers. Tibial nerve SEPs were recorded with 8 leads including Cz'-Cc, Cz'-Ci, C2S-Cc and C2S-Ci. RESULTS: For the Cz'-Ci lead, the P38 potential diminished in amplitude, was absent or became negative. For the C2S-Ci lead, a large negative potential corresponding to the phase reversal of P38 was frequently observed. CONCLUSIONS: Tibial nerve SEPs using the Cz'-Cc or C2S-Cc lead are distorted if the Cc electrode is placed on the opposite side. SIGNIFICANCE: When a strange result is obtained in tibial nerve SEPs, we should check for a right-left error in the Cc electrode placement.

Aquaporin-4-antibody-positive Neuromyelitis Optica Spectrum Disorder in a Patient with Charcot-Marie-Tooth Disease Type 1A.

Charcot-Marie-Tooth disease type 1A (CMT1A) is a hereditary peripheral neuropathy, and its involvement in the central nervous system (CNS) is very rare. We herein report a 51-year-old woman with CMT1A who suffered from recurrent optic neuritis and myelopathy. Under the diagnosis of anti-aquaporin-4 (anti-AQP4) antibody positive neuromyelitis optica spectrum disorder (NMOSD), we treated her successfully with corticosteroids. This is the first report of CMT1A complicated with anti-AQP4-positive NMOSD. Although the coexistence of the two disorders may simply be a coincidence, we speculated that immune cross-reaction between overexpressed peripheral myelin protein 22 and CNS myelin may have caused concomitant CMT1A and NMOSD.

[Hemiplegia cruciata and severe facial pain due to infarction of the cervicomedullary junction: a case report].

We report the case of a 66-year-old female with hemiplegia cruciata and severe facial pain due to infarction of the cervicomedullary junction. She presented to the hospital with complaints of acute-onset left facial pain and gait disturbance. Neurological examination revealed narrow left palpebral fissure, severe left facial pain and hypothermoesthesia, weakness predominantly in the left upper and right lower extremities, decreased pain and temperature sensation in the right lower extremity, decreased vibration sensation in the left lower extremity, hyperreflexia in the left upper extremity, and mild ataxia in the left upper and lower extremities. Brain MRI revealed a high-intensity lesion in the left cervicomedullary junction on diffusion-weighted and fluid-attenuated inversion recovery images. Hemiplegia cruciata due to the pyramidal tract injury at the cervicomedullary junction is an uncommon clinical manifestation. However, in patients with hemiplegia cruciata, identifying the lesion location may be difficult. Clinicians should consider the possibility of pyramidal decussation lesions. Anatomical differences, in the course of pyramidal tract fibers between the upper and lower limbs have been considered in the pyramidal decussation. Hemiplegia cruciata in this case was primarily caused by the impairment of the left upper limb pyramidal fibers after the pyramidal decussation and the right lower limb pyramidal fibers before the pyramidal decussation.

[Severe sensory-motor axonal neuropathy following diabetic ketoacidosis].

We report a case of severe sensory-motor axonal neuropathy on the lower extremities associated with diabetic ketoacidosis (DKA). A sixteen-year-old boy developed coma and admitted to our hospital. We diagnosed him with DKA based on remarkable hyperglycemia, severe acidosis with hyperketonemia. Intensive glycemic control with insulin was immediately started. He had complications of heart failure, rhabdomyolysis, and renal failure, which required intensive care including mechanical ventilation and hemodialysis. When recovered from the critical condition, he noticed severe weakness, numbness, and pain on the lower limbs, and urinary retention. On nerve conduction studies, both motor and sensory action potentials were absent. Serum anti-ganglioside antibodies were negative. Albuminocytologic dissociation was evident in the cerebrospinal fluid. MRI study revealed marked gadolinium enhancement of the cauda equina. After high-dose intravenous immunoglobulin treatment, he was relieved from leg pain, but the leg weakness and bladder bowel dysfunction did not show immediate improvement. It took approximately six months until he became able to stand and walk using ankle orthosis. Acute neuropathy is a rare complication of diabetes mellitus. Painful neuropathy is known to emerge in association with diabetic treatment, but it seldom causes severe motor disturbance. On the other hand, motor-dominant polyneuropathy has been reported to occur acutely along the treatment of DKA and hyperosmolar hyperglycemia syndrome (HHS). Present case and previous cases with DKA and HHS suggest that rapid correction of glucose level is one of the underlying factors of acute neuropathy related with diabetic treatment.

Lymphovenous Anastomosis Aids Wound Healing in Lymphedema: Relationship Between Lymphedema and Delayed Wound Healing from a View of Immune Mechanisms.

Delayed wound healing in lymphedema is assumed to be caused by two reasons, pathophysiological and immunological effects of lymphedema. The aim of this review is to establish how impaired lymphatics alter wound healing pathophysiologically and immunologically, and to propose treatment modalities that can promote wound healing in lymphedema. Lymphaticovenular anastomoses (lymphovenous anastomoses [LVAs]) were performed on patients who had recurrent cellulitis several times with lymphorrhea and developed severe ulcers that were refractory to skin grafts, flaps, and conservative therapy. The lymphorrhea and the ulcer had healed by 4 weeks. Moreover, the lymphedema improved without compression therapy. Lymphedema is characterized pathophysiologically by localized peripheral edema that compresses the microvasculature and lymphatic vasculature and impairs tissue remodeling. Another suspected mechanism is an imbalance in the differentiation of participating immune cells. Profound suppression of T helper (Th)1 cells is likely to increase the risk of infection, and excessive differentiation of Th2 cells, including M2 macrophage polarization, may promote fibrosis, which disrupts the carefully orchestrated wound healing process. Although negative-pressure wound therapy is useful for the treatment of delayed wound healing in lymphedema, LVAs may be necessary to treat the fundamental problem of lymphedema. LVAs are considered to create a bypass to the lymph nodes through which dendritic cells (DCs) can transmit antigen information to T cells. LVAs are considered to neutralize chronic inflammation by allowing more DCs to return into the circulation, thereby improving wound healing.