Background: Mutations in thePleckstrin homology domain-containing, family G member 5(PLEKHG5) gene has been reported in a family harboring an autosomal recessive lower motor neuron disease (LMND). However, thePLEKHG5mutation has not been described to cause Charcot-Marie-Tooth disease (CMT).Methods: To identify the causative mutation in an autosomal recessive intermediate CMT (RI-CMT) family with childhood onset, whole exome sequencing (WES), histopathology, and lower leg MRIs were performed. Expression and activity of each mutant protein were analyzed.Results: We identified novel compound heterozygous (p.Thr663Met and p.Gly820Arg) mutations in thePLEKHG5gene in the present family. The patient revealed clinical manifestations of sensory neuropathy. Fatty replacements in the distal lower leg muscles were more severe than in the thigh muscles. Although the symptoms and signs of this patient harboring slow nerve conduction velocities suggested the possibility of demyelinating neuropathy, a distal sural nerve biopsy was compatible with axonal neuropathy. Immunohistochemical analysis revealed that the patient has a low level of PLEKHG5 in the distal sural nerve and an in vitro assay suggested that the mutant proteins have a defect in activating the NF-κB signaling pathway.Conclusions: This study identifies compound heterozygousPLEKHG5mutations as the cause of RI-CMT. We suggest that PLEKHG5 might play a role in the peripheral motor and sensory nervous system. This study expands the phenotypic spectrum ofPLEKHG5mutations.

Background: Charcot-Marie-Tooth disease (CMT) is a heterogeneous disorder of the peripheral nervous system. So far, mutations in hydroxyacyl-CoA dehydrogenase/3-ketoacyl-CoA thiolase/enoyl-CoA hydratase (trifunctional protein), beta subunit (HADHB) gene exhibit three distinctive phenotypes: severe neonatal presentation with cardiomyopathy, hepatic form with recurrent hypoketotic hypoglycemia, and later-onset axonal sensory neuropathy with episodic myoglobinuria. Methods: To identify the causative and characterize clinical features of a Korean family with motor and sensory neuropathies, whole exome study (WES), histopathologic study of distal sural nerve, and lower limb MRIs were performed. Results: WES revealed that a compound heterozygous mutation in HADHB is the causative of the present patients. The patients exhibited an early-onset axonal sensorimotor neuropathy without episodic myoglobinuria, and showed typical clinical and electrophysiological features of CMT including predominant distal muscle weakness and atrophy. Histopathologic findings of sural nerve were compatible with an axonal CMT neuropathy. Furthermore, they didn’t exhibit any other symptoms of the previously reported HADHB patients. Conclusions: These data implicate that mutation in HADHB gene can also cause early-onset axonal CMT instead of typical manifestations in mitochondrial trifunctional protein (MTP) deficiency. Therefore, this study is the first report of a new subtype of autosomal recessive axonal CMT by a compound heterozygous mutation in HADHB, and will expand the clinical and genetic spectrum of HADHB.

Background and Objectives: Essential thrombocythemia (ET) is a chronic myeloproliferative neoplasm characterized by elevated platelet counts and an increased risk of thrombotic events, including ischemic strokes. Materials and Methods: We conducted a retrospective analysis of data from consecutive ischemic stroke patients with ET between March 2014 and February 2023. Results: This case series describes the clinical presentation, radiological features, and management of five patients with ET-associated ischemic strokes, all harboring the JAK2 mutation. The diverse radiological findings suggest that both large and small vessel diseases may be influenced by the prothrombotic state induced by ET. A significant elevation in platelet count was observed to correlate with the emergence of new acute infarctions in some cases. Conclusions: The study highlights combined use of antiplatelet and cytoreductive therapy in preventing secondary stroke events in patients with ET and JAK2 mutations. The heterogeneity of stroke patterns in this population necessitates a comprehensive understanding of the underlying pathophysiological mechanisms and tailored therapeutic approaches.