Linkage Analysis in Usher Syndrome type I (USH1) Families from Spain

[EN] Usher syndrome (USH) is an autosomal recessive hereditary disorder characterised by congenital sensorineural hearing loss and gradual visual impairment secondary to retinitis pigmentosa (RP). The disorder is clinically and genetically heterogeneous. With regard to Usher type I (USH1), several subtypes have been described, the most frequent being USH1B located on chromosome 11q13.5. Of 18 USHI families studied by linkage analysis, 12 (67%) showed significant lod score values for locus D11S527 (Zmax=14.032, theta=0.000) situated on chromosome 11q. Our findings suggest considerable genetic heterogeneity in the Spanish USH1 population. It is important to note that one of our families linked to the USH1B locus shows interesting intrafamilial clinical variability. As regards the remaining six USH1 families, the linkage analysis did not provide conclusive data, although two of them show slight linkage to markers located on chromosome 3q (Zmax=1.880, theta=0.000 for D3S1279), the same location that had previously been assigned to some USH3 families. The authors would like to thank the patients and their family members for their help and cooperation. We acknowledge the Asociación de retinosis pigmentaria de la Comunidad Valenciana, the FAARPEE, ONCE, Fundación ONCE, and the Fondo de Investigaciones Sanitarias (FISS No 95/1814) for financial support. Espinós-Armero, CÁ.; Nájera, C.; Millán, JM.; Ayuso, C.; Baiget, M.; Pérez-Garrigues, H.; Rodrigo, O... (1998). Linkage Analysis in Usher Syndrome type I (USH1) Families from Spain. Journal of Medical Genetics. 35(5):391-398. https://doi.org/10.1136/jmg.35.5.391 Usher CH. Bowman's lecture: on a few hereditary eye affections. Trans Ophthal Soc UK 1935;55:164-245. Hallgren B Retinitis pigmentosa combined with congenital deafness; with vestibulo-cerebellar ataxia and mental abnormality in a proportion of cases. A clinical and genetico-statistical study. Acta Psychiatr Scand 1959; 34(suppl 138):5-101. Kimberling WJ, Moller CG, Davenport SLH, et al. Usher syndrome: clinical findings and gene localization studies. Laryngoscope 1989;99:66-72. Tamayo ML, Bernal JE, Tamayo GE, et al. Usher syndrome: results of a screening program in Colombia. Clin Genet 1991;40:304-1 1. van Aarem A, Cremers CWRJ, Pinckers AJLG, Huygen PLM, Hombergen GCJH, Kimberling BJ. The Usher syndrome type 2A: clinical findings in obligate carriers. Int Pediatr Otorhinolaryngol 1995;31:159-74. Gorlin RJ, Tilsner TJ, Feinstein S, Duvall AJ. Usher's syndr