New mutations in MID1 provide support for loss of function as the cause of X-linked Opitz syndrome.
Hum Mol Genet
; 9(17): 2553-62, 2000 Oct 12.
Article
em En
| MEDLINE
| ID: mdl-11030761
ABSTRACT
Opitz syndrome (OS) is a genetically heterogeneous malformation disorder. Patients with OS may present with a variable array of malformations that are indicative of a disturbance of the primary midline developmental field. Mutations in the C-terminal half of MID1, an RBCC (RING, B-box and coiled-coil) protein, have recently been shown to underlie the X-linked form of OS. Here we show that the MID1 gene spans at least 400 kb, almost twice the distance originally reported and has a minimum of six mRNA isoforms as a result of the alternative use of 5' untranslated exons. In addition, our detailed mutational analysis of MID1 in a cohort of 15 patients with OS has resulted in the identification of seven novel mutations, two of which disrupt the N-terminus of the protein. The most severe of these (E115X) is predicted to truncate the protein before the B-box motifs. In a separate patient, a missense change (L626P) was found that also represents the most C-terminal alteration reported to date. As noted with other C-terminal mutations, GFP fusion constructs demonstrated that the L626P mutant formed cytoplasmic clumps in contrast to the microtubular distribution seen with the wild-type sequence. Notably, however, both N-terminal mutants showed no evidence of cytoplasmic aggregation, inferring that this feature is not pathognomonic for X-linked OS. These new data and the finding of linkage to MID1 in the absence of a demonstrable open reading frame mutation in a further family support the conclusion that X-linked OS results from loss of function of MID1.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fatores de Transcrição
/
Anormalidades Múltiplas
/
Proteínas Nucleares
/
Ligação Genética
/
Proteínas dos Microtúbulos
/
Mutação
Tipo de estudo:
Prognostic_studies
Limite:
Female
/
Humans
/
Male
Idioma:
En
Revista:
Hum Mol Genet
Assunto da revista:
BIOLOGIA MOLECULAR
/
GENETICA MEDICA
Ano de publicação:
2000
Tipo de documento:
Article