Solving a case of allelic dropout in the GNPTAB gene: implications in the molecular diagnosis of mucolipidosis type III alpha/beta.
J Pediatr Endocrinol Metab
; 29(10): 1225-1228, 2016 Oct 01.
Article
em En
| MEDLINE
| ID: mdl-27710913
ABSTRACT
While being well known that the diagnosis of many genetic disorders relies on a combination of clinical suspicion and confirmatory genetic testing, not rarely, however, genetic testing needs much perseverance and cunning strategies to identify the causative mutation(s). Here we present a case of a thorny molecular diagnosis of mucolipidosis type III alpha/beta, which is an autosomal recessive lysosomal storage disorder, caused by a defect in the GNPTAB gene that codes for the α/ß-subunits of the GlcNAc-1-phosphotransferase. We used both cDNA and gDNA analyses to characterize a mucolipidosis type III alpha/beta patient whose clinical diagnosis was already confirmed biochemically. In a first stage only one causal mutation was identified in heterozygosity, the already described missense mutation c.1196C>T(p.S399F), both at cDNA and gDNA levels. Only after conducting inhibition of nonsense-mediated mRNA decay (NMD) assays and after the utilization of another pair of primers the second mutation, the c.3503_3504delTC deletion, was identified. Our findings illustrate that allelic dropout due to the presence of polymorphisms and/or of mutations that trigger the NMD pathway can cause difficulties in current molecular diagnosis tests.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Transferases (Outros Grupos de Fosfato Substituídos)
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Mucolipidoses
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Mutação
Tipo de estudo:
Diagnostic_studies
/
Prognostic_studies
Limite:
Child, preschool
/
Humans
Idioma:
En
Revista:
J Pediatr Endocrinol Metab
Ano de publicação:
2016
Tipo de documento:
Article