Usher syndrome (USH) is an autosomal recessive syndromic ciliopathy characterized by sensorineural hearing loss, retinitis pigmentosa and, sometimes, vestibular dysfunction. There are three clinical types depending on the severity and age of onset of the symptoms; in addition, ten genes are reported to be causative of USH, and six more related to the disease. These genes encode proteins of a diverse nature, which interact and form a dynamic protein network called the “Usher interactome”. In the organ of Corti, the USH proteins are essential for the correct development and maintenance of the structure and cohesion of the stereocilia. In the retina, the USH protein network is principally located in the periciliary region of the photoreceptors, and plays an important role in the maintenance of the periciliary structure and the trafficking of molecules between the inner and the outer segments of photoreceptors. Even though some genes are clearly involved in the syndrome, others are controversial. Moreover, expression of some USH genes has been detected in other tissues, which could explain their involvement in additional mild comorbidities. In this paper, we review the genetics of Usher syndrome and the spectrum of mutations in USH genes. The aim is to identify possible mutation associations with the disease and provide an updated genotype–phenotype correlation.

Spinal muscular atrophy (SMA) is a degenerative neuromuscular condition resulting from a homozygous deletion of the survival motor neuron 1 (SMN1) gene in 95% of patients. A timely diagnosis via newborn screening (NBS) and initiating treatment before the onset of symptoms are critical for improving health outcomes in affected individuals. We carried out a screening test by quantitative PCR (qPCR) to amplify the exon seven of SMN1 using dried blood spot (DBS) samples. From October 2021 to August 2024, a total of 31,560 samples were tested in the Valencian Community (Spain) and 4 of them were positive for SMA, indicating an incidence of 1/7890. Genetic confirmation was performed using multiplex ligation-dependent probe amplification (MLPA) and AmplideX PCR/CE SMN1/2 Plus kit, in parallel obtaining concordant results in survival motor neuron 2 (SMN2) gene copy number. Within the first few weeks of their lives, two of the four patients detected by NBS showed signs of severe hypotonia, becoming ineligible for treatment. The other two patients were the first presymptomatic patients with two copies of SMN2 to receive treatment with Risdiplam in Spain. In order to treat positive cases in their early stages, we conclude that the official deployment of SMA newborn screening is necessary.

Spinal muscular atrophy (SMA) is a degenerative neuromuscular condition resulting from a homozygous deletion of survival motor neuron 1 (SMN1) gene in 95% of patients. A timely diagnosis via newborn screening (NBS) and initiating treatment before the onset of symptoms are critical for improving health outcomes in affected individuals. We carried out a screening test by quantitative PCR (qPCR) to amplify the exon seven of SMN1 using dried blood spot (DBS) samples. From October 2021 to August 2024 a total of 31,560 samples were tested and four of them were positive for SMA, indicating an incidence of 1/7,890. Genetic diagnosis was performed using multiplex ligation-dependent probe amplification (MLPA) and AmplideX PCR/CE SMN1/2 Plus kit in parallel obtaining concordant results in survival motor neuron 2 (SMN2) gene copy number. Within the first few weeks of their lives, two of the four patients detected by NBS showed signs of severe hypotonia, turning out to be not eligible for treatment. The other two patients were the first presymptomatic patients with two copies of SMN2 to get treatment with Risdiplam in Spain. In order to treat positive cases in early stages, we conclude that the official deployment of SMA newborn screening is necessary.