Author: Francisco Alves (Portugal)
Co-authors: Luisa Santos, Cristina Santos, Guilherme Almeida, Miguel Leitão, Catarina Rodrigues
Usher Syndrome is the association between Retinitis Pigmentosa (RP) with sensorineural hearing loss. Showing autosomal recessive inheritance, there are at least 16 genetic loci identified as associated with Usher Syndrome. With a prevalence of about 3-4 cases per 100.000 persons, there are 4 types of Usher Syndrome. The purpose of this work is to present a family with different genotypes and phenotypes, with the mother having homozygosity to a mutation in USH2A (gene associated with Usher Syndrome), and her son and daughters being compound heterozygotes.
Instituto de Oftalmologia Dr. Gama Pinto
Case reports of 4 patients, from the same family (mother, son and daughters), in which the mother (born from a consanguineous marriage), shows the association between RP and sensorineural hearing loss since her 50 years (Usher Syndrome), and her children only exhibit RP until now. Case 1: Female, 62 years Case 2: Female, 41 years Case 3: Male, 36 years Case 4: Female, 29 years
The following is a summary of the last appointment of the 4 cases: Case 1: The patient refers Nyctalopia, Photophobia, Photopsies, and visual field (VF) loss; Best Corrected Visual Acuity by the Snellen Chart (BCVA 6/10 Right eye (R); 5/10 Left eye (L)); Fundoscopy shows thin vessels and scarce pigmentation in a bone-spicule configuration at the periphery. Scotopic and photopic Electroretinogram (ERG) extint; VF (Goldmann) with Tunnel Vision. Case 2: Patient refers Nyctalopia, Photophobia and Photopsies; BCVA (10/10 R; 10/10 L); Fundoscopy shows mid peripheral Choriorretinal atrophy without pigmentation; VF (Goldmann) shows peripheral constriction. Case 3: The patient refers Photophobia; BCVA (10/10 R; 10/10 L); Fundoscopy shows thin vessels and pigment in a bone-spicule configuration at the periphery. VF (Goldmann) shows peripheral constriction. Case 4: The patient refers Photophobia, VF loss, Nyctalopia and Photopsies; BCVA (10/10 R; 10/10 L); Fundoscopy shows thin vessels and scarce pigmentation in a bone-spicule configuration at the perifery. The son and daughters all had OCTs exhibiting atrophy of the external retinal layers, except at foveal zone.
In a family with an apparent autosomal dominant vertical transmission for RP, sensorineural hearing loss, and consanguinity in the first generation, the result of a genetic test denotes that a compound heterozygosity can explain the vertical transmission in this family. Therefore, the genetic testing can be of vital importance in the identification and prediction of vision loss in some families that show some form of retinal hereditary disease.
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