RESUMO

We describe a child with congenital hypogammaglobulinemia that was diagnosed at 13 months of age. When he was 4 years old, gait disturbances began. The main neurological manifestations were progressive spastic tetraparesis and intellectual and speech deterioration. No infectious agent was identified. A magnetic resonance imaging scan of the central nervous system revealed periventricular demyelinating areas in the frontal, temporal, and parietal lobes with cortical atrophy. Stereotactic brain biopsy confirmed the diagnosis of progressive multifocal leukoencephalopathy caused by JC virus. He was treated with intravenous and intraventricular cytarabine and interferon-alpha, and there was clinical improvement. We emphasize the need for brain biopsy as soon as a neurological complication is suspected in patients with congenital hypogammaglobulinemia for whom cerebrospinal cultures or polymerase chain reaction analyses are negative.

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RESUMO

The identification of mutations in Duchenne or Becker muscular dystrophy (DMD/BMD) patients is important for carrier detection in these families. We present the patterns of deletions of the dystrophin gene in Argentine population. DNA from 75 patients with DMD/BMD was analyzed by multiplex PCR and, in some cases, cDNA/Southern. Deletions were detected in 24 patients (32%) and were mainly clustered in two areas of the dystrophin gene: the 5' end (exons 3-12) and the central part (exons 44-53). 64% of the deletion endpoints lay in the middle region and 34% in the 5' end of the gene. The most frequent sites for deletion-endpoints were in the introns 47 (13.6%), 44 (11%), 2 (9%) and 12 (7%). Thus, the proportion and distribution of deletions in our DMD/BMD patients differ from those reported for other populations. Furthermore, a higher proportion of deletions was observed in familial cases (40%) than in isolated ones (30%), in contrast to previously reported data. The effect of the deletion on the reading frame agree with the phenotype in almost all the patients studied. This study will be useful in prenatal diagnosis and diagnosis of other Argentine DMD patients.

Assuntos

RESUMO

In order to offer carrier detection, genetic counseling, and prenatal diagnosis to families with Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) in our country, segregation analysis of highly polymorphic short tandem repeats (STR) (dC-dA)n: (dG-dT)n loci was utilized. The risks to females of 15 DMD BMD families (9 familial and 6 sporadic) were evaluated on STR, pedigree and serum creatine kinase (SCK) data. From the 36 females at risk of being carriers (not including 8 obligate carriers), results of STR analysis were compatible with carrier status in 7 and not compatible in 20. In 9 females, no information regarding carriership was derived from the STR analysis. Prenatal diagnosis is now possible on the carrier females. Previously identified deletions in the central part of the gene were confirmed by STR analysis in 3 families. Five new alleles were identified in Argentine individuals; allele frequencies differed from those of North American people. Results derived from this study are useful for carrier detection and genetic counseling in DMD/BMD. One case of probable mosaicism in an unaffected father was detected on a pedigree basis in a family with DMD patients.

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RESUMO

One patient with hexosaminidase A (Hx A) deficiency, which produces GM2 gangliosidosis, developed a complex progressive neurological syndrome, starting when he was 10 years old, which encompassed intellectual impairment, cerebellar involvement, features of upper and lower motoneurones compromise and sensory neuropathy without signs of motor fibre damage within the peripheral nerves. Sural nerve biopsy demonstrated loss of myelinated fibres, mainly of those of large and small diameters, clusters of small diameter fibres, fibres with abnormal thin myelin sheaths related to their axonal diameters, axonal degeneration, segmental and paranodal demyelination and remyelination. Electronmicroscopic examination showed small electrondense, non specific, bodies and concentric lamellar inclusions within the cytoplasm of the Schwann cells. These findings demonstrate that pure sensory peripheral neuropathy should be considered as part of the spectrum which may result from Hx A deficiency.

Assuntos

RESUMO

One patient with hexosaminidase A (Hx A) deficiency, which produces GM2 gangliosidosis, developed a complex progressive neurological syndrome, starting when he was 10 years old, which encompassed intellectual impairment, cerebellar involvement, features of upper and lower motoneurones compromise and sensory neuropathy without signs of motor fibre damage within the peripheral nerves. Sural nerve biopsy demonstrated loss of myelinated fibres, mainly of those of large and small diameters, clusters of small diameter fibres, fibres with abnormal thin myelin sheaths related to their axonal diameters, axonal degeneration, segmental and paranodal demyelination and remyelination. Electronmicroscopic examination showed small electrondense, non specific, bodies and concentric lamellar inclusions within the cytoplasm of the Schwann cells. These findings demonstrate that pure sensory peripheral neuropathy should be considered as part of the spectrum which may result from Hx A deficiency.

RESUMO

One patient with hexosaminidase A (Hx A) deficiency, which produces GM2 gangliosidosis, developed a complex progressive neurological syndrome, starting when he was 10 years old, which encompassed intellectual impairment, cerebellar involvement, features of upper and lower motoneurones compromise and sensory neuropathy without signs of motor fibre damage within the peripheral nerves. Sural nerve biopsy demonstrated loss of myelinated fibres, mainly of those of large and small diameters, clusters of small diameter fibres, fibres with abnormal thin myelin sheaths related to their axonal diameters, axonal degeneration, segmental and paranodal demyelination and remyelination. Electronmicroscopic examination showed small electrondense, non specific, bodies and concentric lamellar inclusions within the cytoplasm of the Schwann cells. These findings demonstrate that pure sensory peripheral neuropathy should be considered as part of the spectrum which may result from Hx A deficiency.

RESUMO

A 13-year-old boy with autosomal-dominant congenital facial diplegia was evaluated by electrophysiologic and genetic investigations. Thirteen members of his family were affected over 4 generations. The electrophysiologic studies revealed blink reflex abnormalities. Both R1 and R2 responses were prolonged on the left side after ipsilateral stimulation, while R2 was also delayed by contralateral stimulation. Ipsilateral R1 and R2 were of normal latencies when the right side was stimulated. A third ipsilateral response at 63 msec of latency could be obtained when stimulating the left side. These findings suggest functional damage to the brainstem. Further support for this interpretation was provided by the prolonged time between waves I and V, bilaterally, documented by study of brainstem auditory evoked potentials.

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Twelve patients between 15 months and 13 years of age with clinical and pharmacological features of myasthenia gravis were studied. Repetitive nerve stimulation did not offer valuable information; the patients demonstrated either inspecific muscular decremental response or had normal behavior. Two clear groups of patients were identified after measurements of acetylcholine receptor (AChR) antibodies and MEPP amplitude recorded in the diaphragm of mice injected with sera from those patients. The first group included patients with positive AChR antibodies titers and decreased MEPP amplitude. The second one had negative AChR antibodies titers and MEPPs with normal amplitude. These data strongly suggest immunologic and non-immunologic mechanisms for the former and later respectively.

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Se estudiaron 4 pacientes con un cuadro clínico en el que se combinaron fasciculaciones, contracturas, calambres, parestesias y rigidez muscular progresiva. En ellos se realizó el estudio electrofisiológico que involucró EMG, estudio de la excitabilidad de la motoneurona espinal alfa (MN), del coeficiente de excitabilidad de la MN, de la velocidad de conducción motora y sensitiva, de la transmisión neuromuscular y de la actividad gamma. Los hallazgos evidenciaron compromiso del SNP expresado en reducción del número de unidades motoras (UM), pérdida del trazadoEMG interferencial, presencia de fibrilaciones, fasciculaciones y disminución de la velocidad de conducción motora con preservación de la conducción sensitiva. A ello se sumó aumento de la excitabilidad de la MN alfa evidenciado en la curva de recuperación de la onda H; la relación H/M se halló dentro de límites normales en todos los casos, en tanto que los cocientes T/M y T/H se vieron incrementados en tres de los casos; en dos de los pacientes se realizó el bloqueo gamma, lográndose la desaparición de la actividad contínua de UM. El estudio de la transmisión neuromuscular, período silente y coeficiente de excitabilidad de la MN no mostraron alteraciones. Esta serie de hallazgos sugieren indemnidad de la unión neuromuscular, de los mecanismos inhibitorios segmentarios mediados por interneuronas de acción postsináptica y de las estructuras corticales, señalando un incremento de la actividad de las fibras gamma. La presencia de diferentes cuadros que presentan aspectos signosintomatológicos comunes impulsó una revisión sobre las diferentes entidades clínicas descriptas, pruebas electrofisiológicas utilizadas para su estudio, aspectos etiopatogénicos y la aproximación terapéutica a ellas

Assuntos

RESUMO

Se estudiaron 4 pacientes con un cuadro clínico en el que se combinaron fasciculaciones, contracturas, calambres, parestesias y rigidez muscular progresiva. En ellos se realizó el estudio electrofisiológico que involucró EMG, estudio de la excitabilidad de la motoneurona espinal alfa (MN), del coeficiente de excitabilidad de la MN, de la velocidad de conducción motora y sensitiva, de la transmisión neuromuscular y de la actividad gamma. Los hallazgos evidenciaron compromiso del SNP expresado en reducción del número de unidades motoras (UM), pérdida del trazadoEMG interferencial, presencia de fibrilaciones, fasciculaciones y disminución de la velocidad de conducción motora con preservación de la conducción sensitiva. A ello se sumó aumento de la excitabilidad de la MN alfa evidenciado en la curva de recuperación de la onda H; la relación H/M se halló dentro de límites normales en todos los casos, en tanto que los cocientes T/M y T/H se vieron incrementados en tres de los casos; en dos de los pacientes se realizó el bloqueo gamma, lográndose la desaparición de la actividad contínua de UM. El estudio de la transmisión neuromuscular, período silente y coeficiente de excitabilidad de la MN no mostraron alteraciones. Esta serie de hallazgos sugieren indemnidad de la unión neuromuscular, de los mecanismos inhibitorios segmentarios mediados por interneuronas de acción postsináptica y de las estructuras corticales, señalando un incremento de la actividad de las fibras gamma. La presencia de diferentes cuadros que presentan aspectos signosintomatológicos comunes impulsó una revisión sobre las diferentes entidades clínicas descriptas, pruebas electrofisiológicas utilizadas para su estudio, aspectos etiopatogénicos y la aproximación terapéutica a ellas (AU)

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