Atypical presentation of Charcot-Marie-Tooth disease type 2Q by mutations on DHTKD1 and NTRK2 genes / Presentación atípica de enfermedad de Charcot-Marie-Tooth tipo 2Q por mutaciones en los genes DHTKD1 y NTRK2

Abstract Background: Charcot-Marie-Tooth disease type 2Q (CMT2Q) is a rare disorder (< 1/1,000,000 individuals worldwide) linked to chromosome 10p14 in the DHTKD1 gene. This phenotype is characterized by an adolescent or adulthood-onset, slowly progressive distal muscle weakness and symmetrical atrophy associated with reduced or absent deep tendon reflexes. Currently, only two familiar cases from China have been reported: one familiar case of eight individuals affected by isolated DHTKD1 gene mutation and one familiar case of two individuals affected by DHTKD1 gene mutation and GJB1 gene mutation. Case report: We present the case of a 10-year-old male patient with obesity, frequent falls, swollen legs and thighs, and pain in the lower and upper limbs. We performed the clinical evaluation and a clinical targeted exome test, which reported mutations on DHTKD1 y NTRK2 genes. Conclusions: Due to scientific and technological advances, genetic dysfunctions that can cause different diseases have been identified with greater sensitivity. Globally, this is the eleventh case reported of DHTKD1 gene mutation linked to CMT2Q. Moreover, this is the first case related to NTRK2 gene mutation (linked to obesity, hyperphagia, and delayed development). The patient showed an atypical CMT2Q phenotype additional to obesity. Therefore, we propose to study metabolic disorders linked to hereditary peripheral neuropathies.

Resumen Introducción: La enfermedad de Charcot-Marie-Tooth tipo 2Q (CMT2Q) es una alteración poco frecuente (< 1/1,000,000 habitantes en todo el mundo) condicionada por mutaciones en el gen DHTKD1, localizado en el cromosoma 10p14. El padecimiento inicia en la adolescencia o la edad adulta de manera lenta y progresiva, con debilidad muscular y atrofia distal simétrica, y afecta predominantemente las extremidades inferiores y los reflejos tendinosos profundos, que se encuentran reducidos o ausentes. Solo se ha reportado un caso familiar de ocho personas afectadas con la mutación aislada en el gen DHTKD1 y un caso familiar de dos personas afectadas con mutaciones en los genes DHTKD1 y GJB1, ambas familias de China. Caso clínico: Se presenta el caso de un paciente de sexo masculino de 10 años y 11 meses de edad con obesidad, caídas frecuentes, edema de miembros pélvicos y dolor en las extremidades inferiores y superiores. Se realizaron valoración clínica y estudio genético molecular de exoma dirigido, el cual reportó mutaciones en los genes DHTKD1 y NTRK2. Conclusiones: Gracias al avance científico y tecnológico se han podido identificar con mayor precisión las alteraciones genéticas causantes de diferentes enfermedades. Este es el undécimo caso reportado en el mundo de una mutación en el gen DHTKD1 asociada con la enfermedad de CMT2Q. También es el primer caso relacionado con una mutación del gen NTRK2 (asociada con obesidad, hiperfagia y retraso en el desarrollo). El paciente presentó un cuadro clínico atípico de enfermedad de CMT2Q agregado a obesidad. Por ello, se sugiere estudiar a fondo la conexión entre trastornos metabólicos y neuropatías periféricas hereditarias.

Pé cavo: revisão da literatura / Cavus foot: review

OBJETIVO: Realizar uma revisão sobre o pé cavo, sua fisiopatologia, avaliação clínica, diagnósticos diferenciais com ênfase na doença de Charcot-Marie-Tooth e tratamento. MÉTODO: Revisão não sistemática de artigos abordando a fisiopatologia do pé cavo, avaliação clínica, diagnósticos diferenciais e tratamento. RESULTADOS E DISCUSSÃO: Foram utilizados 33 artigos de língua inglesa e 02 artigos em português para a confecção desta revisão. CONCLUSÃO: O pé cavo é geralmente secundário a doenças neurológicas, em especial a doença de Charcot-Marie-Tooth e raramente é originado por doenças não neurológicas. O diagnóstico etiológico do pé cavo permite um melhor tratamento, cirúrgico ou não, com adequada orientação ao paciente quanto ao prognóstico e eficácia da terapia.

OBJECTIVE: We realize a review about cavus foot, discussing pathophysiology, clinical evaluation, differential diagnosis with emphasis on Charcot-Marie-Tooth Disease and treatment. METHOD: We perform a non-systematic review of articles about cavus foot pathophysiology, physical examination, etiology and treatment. RESULTS AND DISCUSSION: We used 33 articles in english and 02 articles in portuguese for this review. CONCLUSION: The cavus foot is mostly a consequence of neurological etiologies, in particular Charcot-Marie-Tooth disease and rarely is caused by non-neurological diseases. The correct diagnosis allows better treatment, conservative or surgical, with appropriate guidance to patients in terms of prognosis and therapy effectiveness.

Function disability evaluation in hereditary motor and sensory neuropathy pediatric patients / 中华实用儿科临床杂志

Hereditary motor and sensory neuropathy is the most common peripheral neuropathy.It is slowly progressive,proximal limb weakness and muscular dystrophy and severe foot deformity can cause function disability.For most patients were diagnosed in early children,so function disability evaluation and effective treatment from children is significant to their prognosis.

Hereditary Motor and Sensory Neuropathy Type VI with Bilateral Middle Cerebellar Peduncle Involvement

Charcot-Marie-Tooth disease (CMT) 2A with optic atrophy is referred to as hereditary motor and sensory neuropathy type VI (HMSN VI) and is caused by mitofusin 2 gene (MFN2) mutation. In patients with MFN2 related CMT, central nervous system is known to be also involved and cerebral white matter is mostly involved. We report a patient confirmed as HMSN VI who had isolated bilateral middle cerebellar peduncular lesions in brain MRI.

Dynamic Transcriptional Events in Distal Sural Nerve Revealed by Transcriptome Analysis

Compared with biochemical information available about the diseases in the central nervous system, that for peripheral neuropathy is quite limited primarily due to the difficulties in obtaining samples. Characterization of the core pathology is a prerequisite to the development of personalized medicine for genetically heterogeneous diseases, such as hereditary motor and sensory neuropathy (HMSN). Here, we first documented the transcriptome profile of distal sural nerve obtained from HMSN patients. RNA-seq analysis revealed that over 12,000 genes are expressed in distal sural nerve. Among them 4,000 transcripts are novel and 10 fusion genes per sample were observed. Comparing dataset from whole exome sequencing revealed that over 1,500 transcriptional base modifications occur during transcription. These data implicate that dynamic alterations are generated when genetic information are transitioned in distal sural nerve. Although, we could not find significant alterations associated with HMSN, these data might provide crucial information about the pathophysiology of HMSN. Therefore, next step in the development of therapeutic strategy for HMSN might be unveiling biochemical and biophysical abnormalities derived from those potent variation.

Genetics of Hereditary Peripheral Neuropathies

Hereditary peripheral neuropathies can be categorized as hereditary motor and sensory neuropathies (HMSN), hereditary motor neuropathies (HMN), and hereditary sensory neuropathies (HSN). HMSN, HMN, and HSN are further subdivided into several subtypes. Here, we review the most recent findings in the molecular diagnosis and therapeutic strategy for hereditary peripheral neuropathies. The products of genes associated with hereditary peripheral neuropathy phenotypes are important for neuronal structure maintenance, axonal transport, nerve signal transduction, and functions related to the cellular integrity. Identifying the molecular basis of hereditary peripheral neuropathy and studying the relevant genes and their functions is important to understand the pathophysiological mechanisms of these neurodegenerative disorders, as well as the processes involved in the normal development and function of the peripheral nervous system. These advances and the better understanding of the pathogenesis of peripheral neuropathies represent a challenge for the diagnoses and managements of hereditary peripheral neuropathy patients in developing future supportive and curative therapies.

Current Issues of the Charcot-Marie-Tooth Disease

Hereditary motor and sensory neuropathy (HMSN), or Charcot-Marie-Tooth (CMT) disease, was described by Charcot and Marie in France and, independently, by Tooth in England in 1886. CMT is the most common form of inherited motor and sensory neuropathy, and is a genetically heterogeneous group of disorders in the peripheral nervous system. Traditionally, CMT has been subclassified into autosomal dominant inherited demyelinating (CMT1) and axonal (CMT2) neuropathies, X-linked neuropathy (CMTX), and autosomal recessive inherited neuropathy (CMT4). There are several related peripheral neuropathies, such as Dejerine-Sottas neuropathy (DSN), congenital hypomyelination neuropathy (CHN), hereditary neuropathy with liability to pressure palsies (HNPP), and giant axonal neuropathy (GAN). A large amount of new information on the genetic causes of CMT has become available, and mutations causing the disease have been associated with more than 20 different genes and 40 chromosomal loci. Advances in our understanding of the molecular basis of CMT have revealed an enormous diversity in genetic mechanisms, despite the clinical entity that is relatively uniform at presentation. Recent studies have shown therapeutic effects of certain chemicals in animal models of CMT1A, which suggests potential therapies for the most common form of CMT, CMT1A. This review focuses on the subgroups of inherited motor and sensory neuropathy on which there has been an explosion of new molecular genetic information over the past decade.

A Case of Hereditary Motor and Sensory Neuropathy Type III

Hereditary motor and sensory neuropathy type III, which is also known as Dejerine-Sottas disease, is a severe demyelinating polyneuropathy which presents from birth or infancy, and is sometimes presented as a hypotonic or floppy infant. The disease is inherited autosomal recessively and includes clinical findings of generalized muscle weakness and atrophy, with the greatest severity in distal limb muscles, areflexia, and sensory loss. The disease is characterized histologically by segmental demyelination, remyelination of the peripheral nerves, and onion bulb formations. We experienced a 12-month-old girl with delayed development, frequent respiratory infection and pes cavus. We report this case with a review of related literature.

Study on Brain Evoked Potential about Hereditary Motor and Sensory Neuropathy: Report of 13 Cases in a Family / 第二军医大学学报

This paper reports BAEP, SEP and VEP of 13 patients with hereditary motor and sensory neuropathy in a family. The results showed that 56 target parameters (86.2%) were abnormal in 65 target parameters of BAEP, and SEP of 12 (92.3%) in 13 cases were abnormal, demonstrating that the passageways of peripheral nerve and central nerve were damaged at the same time. VEP of 10 (76.9%) in 13 cases were abnormal. It is concluded that BAEP, SEP and VEP of these patients are significant different from normals (P