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Keywords:

  • frameshift mutation;
  • gene insertion;
  • hemangioblastoma;
  • retinal tumour;
  • von Hippel-Lindau;
  • VHL

Abstract

Background:  von Hippel-Lindau disease (VHL) is an uncommon autosomal dominant condition predisposing to the development of tumours in a variety of body organs and caused by germline mutations in VHL, a tumour suppressor gene located on 3p. Up to 60% of VHL patients show ocular involvement with retinal hemangioblastoma being the most common observed lesion. In this study, we describe the clinical and genetic characteristics of two familial and one apparently non-familial case of VHL ascertained at our institution.

Methods:  Clinical evaluation included ophthalmologic examination and imaging exams for tumours identification; molecular analysis consisted of PCR amplification of the complete VHL gene coding sequence (three exons) and automated nucleotide sequencing.

Results:  A total of eight affected subjects were demonstrated to carry a causative mutation in VHL. Affected subjects from family #1 had a c.245G > C change, predicting a p.R82P substitution, affected individuals from family #2 were shown to have a c.266T > C change, leading to a p.L89P missense substitution, whereas the apparently non-familial case had a c.298-299insA mutation. One subject from family #2 was a non-penetrant carrier. No ocular anomalies were found in two adult affected subjects carrying the p.L89P mutation.

Conclusion:  Considerable interfamilial and intrafamilial clinical variability as well as one instance of non penetrance were recorded in these VHL disease cases. Three different mutations were demonstrated, including the c.298-299insA one base insertion, which has been previously described in two unrelated families from our country. Although additional studies are needed, our data suggest that this insertion could be a ‘founder’ mutation.