RESUMEN
Spinal muscular atrophy (SMA) is a disorder characterized by degeneration of lower motor neurons and occasionally bulbar motor neurons leading to progressive limb and trunk paralysis as well as muscular atrophy. Three types of SMA are recognized depending on the age of onset, the maximum muscular activity achieved, and survivorship: SMA1, SMA2, and SMA3. The survival of motor neuron (SMN) gene has been identified as an SMA determining gene, whereas the neuronal apoptosis inhibitory protein (NAIP) gene is considered to be a modifying factor of the severity of SMA. The main objective of this study was to analyze the deletion of SMN1 and NAIP genes in southern Chinese children with SMA. Here, polymerase chain reaction (PCR) combined with restriction fragment length polymorphism (RFLP) was performed to detect the deletion of both exon 7 and exon 8 of SMN1 and exon 5 of NAIP in 62 southern Chinese children with strongly suspected clinical symptoms of SMA. All the 32 SMA1 patients and 76% (13/17) of SMA2 patients showed homozygous deletions for exon 7 and exon 8, and all the 13 SMA3 patients showed single deletion of SMN1 exon 7 along with 24% (4/17) of SMA2 patients. Eleven out of 32 (34%) SMA1 patients showed NAIP deletion, and none of SMA2 and SMA3 patients was found to have NAIP deletion. The findings of homozygous deletions of exon 7 and/or exon 8 of SMN1 gene confirmed the diagnosis of SMA, and suggested that the deletion of SMN1 exon 7 is a major cause of SMA in southern Chinese children, and that the NAIP gene may be a modifying factor for disease severity of SMA1. The molecular diagnosis system based on PCR-RFLP analysis can conveniently be applied in the clinical testing, genetic counseling, prenatal diagnosis and preimplantation genetic diagnosis of SMA.
Asunto(s)
Eliminación de Gen , Proteína Inhibidora de la Apoptosis Neuronal/genética , Polimorfismo de Nucleótido Simple/genética , Atrofias Musculares Espinales de la Infancia/epidemiología , Atrofias Musculares Espinales de la Infancia/genética , Proteína 1 para la Supervivencia de la Neurona Motora/genética , Niño , Preescolar , China/epidemiología , Femenino , Predisposición Genética a la Enfermedad/epidemiología , Predisposición Genética a la Enfermedad/genética , Humanos , Incidencia , Lactante , MasculinoRESUMEN
Cutaneous pili migrans and creeping eruption caused by parasitic diseases may present as a moving linear lesion in skin. The former, caused by a hair shaft or fragment embedded in the superficial skin or middle dermis, is a rare condition characterized by creeping eruption with a black line observed at the advancing end. In exceptionally rare instance, the hair grows inside the skin and burrows in the uppermost dermis, such a condition has been called "ingrown hair."We report a 30-year-old Chinese man, who was accustomed to pull or extrude the beard hairs, with 1-year history of slowly extending black linear eruption on his right chin. Cutaneous examination revealed a 4-cm long black linear lesion beneath the skin associated with edematous erythema around and folliculitis on both ends of the lesion. After treatment with topical mupirocin ointment, the erythema and folliculitis improved and 2 hairs of the beard with hair follicles were pulled out from the skin. Two weeks later, another similar black line about 1âcm in length in the skin presented on the prior lesional area, which was pulled out by a shallow incision of the skin and was also demonstrated as a beard hair with hair follicle.The patient was diagnosed as "ingrowing hair" with multiple recurrences. The lesions recovered after the beard hairs were pulled out. No recurrence occurred in a year of follow-up.We suggest that "ingrowing hair" is better than "ingrown hair" to describe such a condition. Pulling out the involved hair and correcting the bad practice are its optimal management strategies.