Abstracts

Recent studies have demonstrated that mutations in [italic]FLN1[/italic] gene are responsible for bilateral periventricular nodular heterotopia (BPNH). We identified a novel mutation (1159G[gt]C), in a family segregating BPNH. However, the exact molecular mechanism by which this mutation lead to abnormal FLN1 protein was unclear. The purpose of this study was to investigate the molecular mechanism of this new mutation., Total RNA was obtained from peripheral blood samples, from 2 BPNH patients (mother and daughter) and control individuals. RT-PCR was performed by standard techniques and the cDNA was amplified using specific primers spanning the region containing exon 6 and exon7. Amplicons were cloned into pGEM-T vector, gel-purified and subsequently sequenced, using SP6 and T7 primers., Analysis of the cDNA amplicon demonstrated a different pattern of electrophoretic migration between patients and controls. The sequencing of these fragments showed that amplicons from individuals with BPNH kept the intronic sequence between exons 6 and 7., Our data clearly showed that the molecular mechanism of the mutation 1159G[gt]C is the abolishment of the exon 6 donor splicing, resulting in an alternative stop codon and, possibly, in a truncated protein. Thus an aminoacid substitution, as suggested previously, is not the mechanism involved in the etiology of BPNH sydrome in the patients analysed., (Supported by FAPESP.)