Non-dystrophic myotonia Chilean cohort with predominance of the SCN4A Gly1306Glu variant.

Non-dystrophic myotonias are a group of rare neuromuscular diseases linked to SCN4A or CLCN1. Among the subtypes, myotonia permanens, associated with the Gly1306Glu variant of SCN4A, is a relatively less frequent but more severe form. Most reports of non-dystrophic myotonias describe European populations. Therefore, to expand the genetic and phenotypic spectrum of this disorder, we evaluated 30 Chilean patients with non-dystrophic myotonias for associated variants and clinical characteristics. SCN4A variants were observed in 28 (93%) of patients, including 25 (83%) with myotonia permanens due to the Gly1306Glu variant. Myotonia permanens was inherited in 24 (96%) patients; the mean age of onset was 6 months, and the initial symptoms were orbicularis oculi myotonia in 17 (74%) patients and larynx myotonia in 12 (52%) patients. The extraocular muscles were involved in 11 (44%) patients, upper limbs in 20 (80%), and lower limbs in 21 (84%). Thirteen (52%) patients experienced recurrent pain and 10 (40%) patients reported limitations in daily life activities. Carbamazepine reduced myotonia in eight treated patients. The high frequency of the Gly1306Glu variant in SCN4A in Chilean patients suggests a founder effect and expands its phenotypic spectrum.

Enfoque clínico del recién nacido y lactante hipotónico / Neonatal hypotonia

El síndrome del niño hipotónico es una entidad bien reconocida por pediatras y neonatólogos. Se refiere a un niño con hipotonía generalizada presente desde el nacimiento o infancia precoz. Es el signo de disfunción neurológica más frecuente en el recién nacido y lactante, resultado de injurias agudas o crónicas a cualquier nivel del sistema nervioso, desde la corteza cerebral al músculo. Por la multiplicidad de causas y condiciones que subyacen a la hipotonía es imprescindible un enfoque ordenado y sistemático en la evaluación del niño hipotónico.

Floppy infant syndrome is a well recognized entity for pediatricians and neonatologists. It refers to a child with decreased muscle tone present at birth or in early infancy. It is the commonest sign of neurological dysfunction in newborns and infants, which can result from acute or chronic injuries at any level of the nervous system from cerebral cortex to muscle. Because of the multiple causes and conditions underlying hypotonia, asystematic assessment is essential in the approach to the floppy infant.

Enfrentamiento de macrocefalia en niños / Management of macrocephaly in children

En la mayoría de los niños con macrocefalia no se encuentra una causagrave, sin embargo, deben considerarse en el diagnóstico etiológico cuadros tratables y/o progresivos como una hidrocefalia. Un análisis cuidadoso y ordenado de los datos obtenidos en anamnesis y examen físico/neurológico, y una adecuada valoración del desarrollo psicomotor permitirán definir las probables causas de la macrocefalia y exámenes complementarios, evitando realizar procedimientos innecesarios.

Although most children with macrocephaly do not have a serious cause, treatable or progressive disorders as hydrocephalus must be considered in the diagnostic workup. A careful and orderly analysis of data obtained from anamnesis and physical / neurological examination, and a proper assessment of psychomotor development will allow the definition of likely causes of macrocephaly and examinations to accomplish, avoiding performing unnecessary procedures.

Parálisis cerebral / Cerebral palsy

Parálisis cerebral es un término que define una serie de trastornos motores de origen cerebral, no progresivos que constituyen la causa más frecuente de discapacidad motora en la infancia. No obstante ser una denominación “antigua”, no ha perdido vigencia ni valor si se le utiliza como término sindromático que supone un estudio etiológico acucioso y una conducta terapéutica que incluye múltiples áreas de intervención y de especialistas coordinados a fin de lograr la máxima funcionalidad posible del niño desde el punto de vista motor, intelectual, de comunicación y la máxima integración social, teniendo en cuenta que el grado de desarrollo de una sociedad se mide por el cuidado que otorga a sus minusválidos.

Cerebral palsy (CP) results from a static brain lesion during pregnancy or early life and remains the most common cause of physical disability in children. Despite being an "old" name, it has not lost its usefulness if used as syndromic term that implies a thorough etiologic study and a therapeutic approach that includes multiple areas of intervention and coordinated work of specialists in order to achieve the maximum possible functionality, optimizing motor, intellectual, communication and social integration, considering that the degree of development of a society is measured by the care given to its disabled people.