Hybrids monosomal for human chromosome 5 reveal the presence of a spinal muscular atrophy (SMA) carrier with two SMN1 copies on one chromosome.
Hum Genet
; 108(2): 109-15, 2001 Feb.
Article
en En
| MEDLINE
| ID: mdl-11281448
ABSTRACT
We have analyzed the survival motor neuron gene (SMN1) dosage in 100 parents of children with homozygous SMN1 deletions. Of these parents, 96 (96%) demonstrated the expected one-copy SMN1 carrier genotype. However, four parents (4%) were observed to have a normal two-copy SMN1 dosage. The presence of two intact SMN1 genes in the parent of an affected child indicates either the occurrence of a de novo mutation event or a situation in which one chromosome has two copies of SMN1, whereas the other is null. We have separated individual chromosomes from two of these parents with two-copy SMN1 dosage by somatic cell hybridization and have employed a modified quantitative dosage assay to provide direct evidence that one parent is a two-copy/ zero-copy SMN1 carrier, whereas the other parent had an affected child as the result of a de novo mutation. These findings are important for assessing the recurrence risk of parents of children with spinal muscular atrophy and for providing accurate family counseling.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Cromosomas Humanos Par 5
/
Atrofia Muscular Espinal
/
Tamización de Portadores Genéticos
/
Proteínas del Tejido Nervioso
Límite:
Humans
Idioma:
En
Revista:
Hum Genet
Año:
2001
Tipo del documento:
Article
País de afiliación:
Estados Unidos