[Genetic counselling in visual and auditory disorders].
OBJECTIVE
Inherited retinal dystrophies and hearing loss disorders have a broad clinical and genetic heterogeneity. Over the last decade there have been major advances in our understanding of the molecular pathology of these diseases; currently over 200 genes and loci are known to be involved in retinal disorders, and over 60 genes/loci are causative for hearing impairment.


METHODS
Genetic testing is crucial for confirming the diagnosis at a molecular level. It also allows a more precise prognosis to be made of the future clinical evolution, as well as an accurate genetic and reproductive counselling, and raises the possibility of creating genetically homogeneous groups of patients for future clinical trials.


RESULTS
The high number of genes responsible for these disorders makes molecular testing overwhelming in terms of cost, time and technical effectiveness, and no centre offers testing of all known genes. Several diagnostic tools have emerged recently to circumvent this problem.


CONCLUSIONS
In this report, we review the vast genetic heterogeneity of retinal dystrophies and hypoacusis, recent advances in gene discovery, the different DNA-based microarray technologies available for molecular testing, their benefits and limitations, and novel therapeutic approaches.
Millán
J M
JM
Unidad de Genética, Hospital Universitario La Fe y Departamento de Genética, Universidad de Valencia y Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Valencia, Spain. millan_jos@gva.es
Aller
E
E
Jaijo
T
T
Grau
E
E
Beneyto
M
M
Nájera
C
C
D005307:Fertilization in Vitro; D005544:Forecasting; D005796:Genes; D005817:Genetic Counseling; D018740:Genetic Heterogeneity; D006311:Hearing Disorders / Q000175:diagnosis / Q000235:genetics* / Q000517:prevention & control / Q000628:therapy; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis / Q000235:genetics / Q000517:prevention & control / Q000628:therapy; D006801:Humans; D025202:Molecular Diagnostic Techniques; D020411:Oligonucleotide Array Sequence Analysis; D019836:Preimplantation Diagnosis; D012164:Retinal Diseases / Q000175:diagnosis / Q000235:genetics* / Q000517:prevention & control / Q000628:therapy; D015792:Retinal Dysplasia / Q000175:diagnosis / Q000235:genetics / Q000517:prevention & control / Q000628:therapy; D018570:Risk Assessment; D013577:Syndrome