RESUMEN
OBJECTIVE: To determine the number of primary laminin alpha2 gene mutations and to conduct genotype/phenotype correlation in a cohort of laminin alpha2-deficient congenital muscular dystrophy patients. BACKGROUND: Congenital muscular dystrophies (CMD) are a heterogeneous group of muscle disorders characterized by early onset muscular dystrophy and a variable involvement of the CNS. Laminin alpha2 deficiency has been reported in about 40 to 50% of cases of the occidental, classic type of CMD. Laminin alpha2 is a muscle specific isoform of laminin localized to the basal lamina of muscle fibers, where it is thought to interact with myofiber membrane receptor, such as integrins, and possibly dystrophin-associated glycoproteins. METHODS: Seventy-five CMD patients were tested for laminin alpha2 expression by immunofluorescence and immunoblot. The entire 10 kb laminin alpha2 coding sequence of 22 completely laminin alpha2-deficient patients was screened for causative mutations by reverse transcription (RT)-PCR/single strand conformational polymorphisms (SSCP) analysis and protein truncation test (PTT) analysis followed by automatic sequencing of patient cDNA. Clinical data from the laminin alpha2-deficient patients were collected. RESULTS: Thirty laminin alpha2-negative patients were identified (40% of CMD patients tested) and 22 of them were screened for laminin alpha2 mutations. Clinical features of laminin alpha2-deficient patients were similar, with severe floppiness at birth, delay in achievement of motor milestones, and MRI findings of white matter changes with normal intelligence. Loss-of-function mutations were identified in 95% (21/22) of the patients studied. SSCP analysis detected laminin alpha2 gene mutations in about 50% of the mutant chromosomes; PTT successfully identified 75% of the mutations. A two base pair deletion mutation at position 2,096-2,097 bp was present in 23% of the patients analyzed. CONCLUSIONS: Our data suggest that the large majority of laminin alpha2-deficient patients show laminin alpha2 gene mutations.
Asunto(s)
Laminina/genética , Distrofias Musculares/congénito , Distrofias Musculares/genética , Secuencia de Bases , Biopsia , Niño , Preescolar , Análisis Mutacional de ADN , Femenino , Técnica del Anticuerpo Fluorescente , Eliminación de Gen , Genotipo , Humanos , Lactante , Laminina/análisis , Masculino , Datos de Secuencia Molecular , Músculo Esquelético/química , Músculo Esquelético/patología , Distrofias Musculares/patología , Mutación , Fenotipo , Polimorfismo GenéticoRESUMEN
A percutaneous computed tomography (CT) guided pinning of experimentally reproduced slipped capital femoral epiphysis in five cadavers and one patient--who had bilateral pinning for moderate and severe grade chronic slip--was conducted. Prior investigations of cadavers revealed that this procedure can be performed in selected cases. The details of the technique are illustrated in this article.