title: Clinical and genetic studies in a family with a new splice-site mutation in the choroideremia gene.
abstract: OBJECTIVE
  To describe the clinical and molecular findings of an Italian family with a new mutation in the choroideremia (CHM) gene.
  
  
  METHODS
  We performed a comprehensive ophthalmologic examination, fundus photography, macular optical coherence tomography, perimetry, electroretinography, and fluorescein angiography in an Italian family. The clinical diagnosis was supported by western blot analysis of lymphoblastoid cell lines from patients with CHM and carriers, using a monoclonal antibody against the 415 C-terminal amino acids of Rab escort protein-1 (REP-1). Sequencing of the CHM gene was undertaken on genomic DNA from affected men and carriers; the RNA transcript was analyzed with reverse transcriptase-PCR.
  
  
  RESULTS
  The affected men showed a variability in the rate of visual change and in the degree of clinical and functional ophthalmologic involvement, mainly age-related, while the women displayed aspecific areas of chorioretinal degeneration. Western blot did not show a detectable amount of normal REP-1 protein in affected men who were hemizygous for a novel mutation, c.819+2T>A at the donor splicing site of intron 6 of the CHM gene; the mutation was confirmed in heterozygosity in the carriers.
  
  
  CONCLUSIONS
  Western blot of the REP-1 protein confirmed the clinical diagnosis, and molecular analysis showed the new in-frame mutation, c.819+2T>A, leading to loss of function of the REP-1 protein. These results emphasize the value of a diagnostic approach that correlates genetic and ophthalmologic data for identifying carriers in families with CHM. An early diagnosis might be crucial for genetic counseling of this type of progressive and still untreatable disease.
authors.affiliation: NESMOS Department-Ophthalmology, School of Medicine and Psychology, University "La Sapienza," Rome, Italy.
authors.forename: Maria T
authors.initials: MT
authors.lastname: Contestabile
authors.affiliation: Department of Clinical and Molecular Medicine, School of Medicine and Psychology University "La Sapienza," Rome, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Piane
authors.affiliation: NESMOS Department-Ophthalmology, School of Medicine and Psychology, University "La Sapienza," Rome, Italy.
authors.forename: Nikhil C
authors.initials: NC
authors.lastname: Cascone
authors.affiliation: NESMOS Department-Ophthalmology, School of Medicine and Psychology, University "La Sapienza," Rome, Italy.
authors.forename: Nadia
authors.initials: N
authors.lastname: Pasquale
authors.affiliation: NESMOS Department-Ophthalmology, School of Medicine and Psychology, University "La Sapienza," Rome, Italy.
authors.forename: Angela
authors.initials: A
authors.lastname: Ciarnella
authors.affiliation: NESMOS Department-Ophthalmology, School of Medicine and Psychology, University "La Sapienza," Rome, Italy.
authors.forename: Santi M
authors.initials: SM
authors.lastname: Recupero
authors.affiliation: Department of Clinical and Molecular Medicine, School of Medicine and Psychology University "La Sapienza," Rome, Italy.
authors.forename: Luciana
authors.initials: L
authors.lastname: Chessa
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics* / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D015794:Choroideremia / Q000235:genetics* / Q000473:pathology* / Q000503:physiopathology; D004252:DNA Mutational Analysis; D004596:Electroretinography; D005190:Family; D005260:Female; D005451:Fluorescein Angiography; D005654:Fundus Oculi; D006801:Humans; D015151:Immunoblotting; D007558:Italy; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D010375:Pedigree; D010641:Phenotype; D022821:RNA Splice Sites / Q000235:genetics*; D041623:Tomography, Optical Coherence; D014794:Visual Fields; D055815:Young Adult
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C081787:CHM protein, human; D022821:RNA Splice Sites