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Carrier Screening For Inherited Genetic Conditions
Published in Vincenzo Berghella, Obstetric Evidence Based Guidelines, 2022
Whitney Bender, Lorraine Dugoff
Clinical features: This syndrome is associated with the same features as Usher syndrome type 1F. In contrast to type 1F, however, hearing loss develops later in childhood and retinitis pigmentosa develops in the second decade.
Neonatal adrenoleukodystrophy/disorders of peroxisomal biogenesis
Published in William L. Nyhan, Georg F. Hoffmann, Aida I. Al-Aqeel, Bruce A. Barshop, Atlas of Inherited Metabolic Diseases, 2020
William L. Nyhan, Georg F. Hoffmann, Aida I. Al-Aqeel, Bruce A. Barshop
Hepatomegaly may be progressive [3]. Levels of transaminase activity in the blood may be elevated [3]. With time, there is little evidence of developmental progress. One patient could smile and roll from supine position at between seven and nine months, but lost these functions shortly thereafter. Another developed some lateral head movement and a smile, which she lost after 12 months [3]. One patient had a cataract [3]. Most patients have died before the second birthday [1, 3, 9]. Mean age of death of the patients was 15 months, while in classical Zellweger syndrome it was 5.7 months. In neonatal ALD, death has occurred as early as four months. A small number of patients have survived to teenage, albeit severely handicapped and dysmorphic, while some patients with infantile Refsum disease have reached adulthood [24, 25]. Impaired hearing and retinopathy have suggested a diagnosis of Usher syndrome. The mental age of patients has seldom exceeded 12 months and some have regressed at three to five years.
Genomics and Hearing Loss: Toward a New Standard of Care?
Published in Stavros Hatzopoulos, Andrea Ciorba, Mark Krumm, Advances in Audiology and Hearing Science, 2020
Myosins are actin-based molecular motors that regulate several processes, such as the rearrangement of the actin cytoskeleton, the regulation of tension of actin filaments and the transport of organelles. Several mutations affecting the myosins are well identified (MYO3A, MYO6, MYO7A, and MYO15A for example). Most of the mutations in MYO7A cause Usher syndrome type I, an autosomal recessive genetic disorder characterized by congenital, bilateral, profound sensorineural hearing loss, vestibular areflexia, and adolescent-onset retinitis pigmentosa. Usher syndrome represents about half of cases where both blindness and hearing impairments are present.
Cochlear implantation in children under 12 months: Prevalence and implications of ‘hidden’ disabilities
Published in Cochlear Implants International, 2020
David R. Friedmann, Kaitlyn M. Tona, J. Thomas Roland, Emily R. Spitzer, Susan B. Waltzman
The etiology of hearing loss in the group without concerns preoperatively and without additional diagnoses expected to influence CI performance included genetic causes in 58.1% (43/74) with or without a family history. Mutations in the GJB2gene were specifically documented in 17 of these cases. Three other patients in this group had Usher syndrome diagnosed only later as the etiology of their hearing loss which led to other sensory issues including loss of visual acuity and blindness, but not expected to impact directly on CI performance. Other etiologies discovered later such as Waardenburg syndrome (n = 2) would also not be expected to impact performance with CI. In this group, 24 patients were tested using LNT/MLNT, 28 were tested using PBK words, and 15 were tested using CNC words. Mean scores were 85.5%, 92%, and 86.67% correct, respectively, as in Table 1. Seven patients were not able to complete one of these speech perception tests and instead were tested using GASP words (n = 3, mean score: 82.7%) or IT-MAIS (n = 4, mean score: 67.5%). One patient had speech detection only.
Psychosocial determinants associated with quality of life in people with usher syndrome. A scoping review
Published in Disability and Rehabilitation, 2020
Marine Arcous, Olivier Putois, Sophie Dalle-Nazébi, Sylvain Kerbourch, Anaelle Cariou, Ines Ben Aissa, Sandrine Marlin, Rémy Potier
Usher Syndrome is an autosomal recessive condition characterized by partial or total auditory and visual deficit. Auditory deficit is almost always congenital and due to the sensorineural hearing loss, whereas visual deficit is inevitably progressive and caused by retinitis pigmentosa. Sensorineural hearing loss is due to abnormalities of the inner ear, auditory pathways, and cortical hearing centers, such as damage of nerve and some cochlear hair cells. Sensorineural hearing loss accounts for about 90% of hearing loss reported. When hair cells and neurons are damaged or destroyed, they do not naturally regenerate and cause irreversible hearing loss. Therefore, this type of deafness is generally permanent and can be mild, moderate, severe, profound, or total [3]. On the other hand, retinitis pigmentosa is characterized by a progressive loss of photoreceptors, associated with pigment epithelium dysfunctions. Retinitis pigmentosa leads to chronic inflammation of the retina, which produces black patches affecting darkness vision creating night-blindness (the inability to see at dusk), which results in “tunnel vision” during teenage years. The size of the tunnel vision is variable, usually representing between 5 and 10 degrees of the visual angle [4]. Dischromatopsy, usually known as “colorblindness,” also occurs sometimes [5]. Additional vestibular dysfunctions appear in some patients, leading to equilibrium disorders [6].
Living with type I Usher syndrome: insights from patients and their parents
Published in Ophthalmic Genetics, 2020
Aude Roborel de Climens, Béatrice Tugaut, Andrea Piscopo, Benoit Arnould, Ronald Buggage, Catherine Brun-Strang
Usher syndrome is a rare genetic disorder which is responsible for a significant proportion of deaf-blindness and is the most common condition that affects both hearing and vision (1). Availability of new molecular technologies in the last decade has led to an upward revision of the estimated prevalence figures for Usher syndrome which is now estimated to be around 1/6,000 in the general American population (2). Usher syndrome is characterized by partial or total hearing loss, vestibular dysfunction resulting in problems maintaining balance, and vision loss as a result of an ocular disorder called retinitis pigmentosa (RP). RP causes night-blindness and a loss of peripheral vision (side vision) through the progressive degeneration of the retina. The onset of RP associated with Usher syndrome usually occurs during childhood. As RP progresses, the field of vision narrows due to the degeneration of rod photoreceptors until only central vision (the ability to see straight ahead) remains, a condition known as “tunnel vision” (1). This is typically followed by a progressive loss of central visual acuity due to the subsequent degeneration of cone photoreceptors. On average, patients with Usher syndrome have been reported to reach the threshold for blindness as defined by visual field constriction (visual field less than 20 degrees in the better seeing eye) as early as the fourth decade and by reduced central visual acuity (less than 20/200 or 0.1 (Snellen) in the better seeing eye) as early as the fifth decade (3).