-
Indian Journal of Ophthalmology Jul 2022To study the retinal and choroidal thickness variations on enhanced depth imaging optical coherence tomography scans in ocular albinism (OA) and compare with age-matched... (Observational Study)
Observational Study
PURPOSE
To study the retinal and choroidal thickness variations on enhanced depth imaging optical coherence tomography scans in ocular albinism (OA) and compare with age-matched healthy subjects.
METHODS
This retrospective observational study had 48 eyes of 24 patients diagnosed clinically as OA and age, sex, and axial length-matched control healthy subjects. All patients underwent detailed ophthalmic examination and a single-line horizontal-raster enhanced depth imaging - optical coherence tomography scan (Spectralis, Heidelberg Engineering). Retinal and choroidal thickness was measured, compared, and analyzed between the two groups. Mann-Whitney U test was used for analysis between the two groups. P < 0.05 was considered significant.
RESULTS
The mean age was 28.3 ± 11.6 and 29.9 ± 10.6 years in the OA group and control group, respectively. Spherical equivalents ranged from -8.5D to +10.5D in the OA group and from -8.0D to +10.0D in the control group. The mean axial length between the two groups (P = 0.652) were comparable. The average retinal thickness (272 ± 34.3 vs. 213 ± 13.8 μm; P < 0.001) was greater in the OA group as compared to controls. The mean choroidal thickness (184 ± 78.4 vs. 287 ± 46.4 μm; P < 0.001) was significantly thinner in the OA group.
CONCLUSION
Acquisition of OCT scans in OA can be challenging. This study showed that the subfoveal retinal thickness and choroidal thickness measured across the scans were significantly different in the OA group compared to controls. In the future, more studies are required to evaluate the role of the choroid and its relationship to emmetropization in albinism.
Topics: Adolescent; Adult; Albinism, Ocular; Choroid; Humans; Retina; Retrospective Studies; Tomography, Optical Coherence; Young Adult
PubMed: 35791146
DOI: 10.4103/ijo.IJO_2907_21 -
Journal of Neuroscience Research Jan 2019Albinism, typically characterized by decreased melanin synthesis, is associated with significant visual deficits owing to developmental changes during neurosensory... (Review)
Review
Albinism, typically characterized by decreased melanin synthesis, is associated with significant visual deficits owing to developmental changes during neurosensory retina development. All albinism is caused by genetic mutations in a group of diverse genes including enzymes, transporters, G-protein coupled receptor. Interestingly, these genes are not expressed in the neurosensory retina. Further, regardless of cause of albinism, all forms of albinism have the same retinal pathology, the extent of which is variable. In this review, we explore the possibility that this similarity in retinal phenotype is because all forms of albinism funnel through the same final common pathway. There are currently seven known genes linked to the seven forms of ocular cutaneous albinism. These types of albinism are the most common, and result in changes to all pigmented tissues (hair, skin, eyes). We will discuss the incidence and mechanism, where known, to develop a picture as to how the mutations cause albinism. Next, we will examine the one form of albinism which causes tissue-specific pathology, ocular albinism, where the eye exhibits the retinal albinism phenotype despite near normal melanin synthesis. We will discuss a potential way to treat the disease and restore normal retinal development. Finally, we will briefly discuss the possibility that this same pathway may intersect with the most common cause of permanent vision loss in the elderly.
Topics: Albinism, Ocular; Eye Proteins; Humans; Melanins; Membrane Glycoproteins; Mutation; Pigmentation; Retina; Retinal Pigment Epithelium
PubMed: 29761529
DOI: 10.1002/jnr.24246 -
Journal of Optometry 2023To describe the prevalence and severity of photosensitivity in patients with albinism, and to compare with ocular features and how this correlated with use and choice of...
PURPOSE
To describe the prevalence and severity of photosensitivity in patients with albinism, and to compare with ocular features and how this correlated with use and choice of optical filters.
METHODS
Cross-sectional study on 81 participants with ocular or oculocutaneous albinism. An ophthalmic evaluation including visual acuity, contrast sensitivity and evaluation of iris translucency and fundus hypopigmentation was performed. Participants were offered optical rehabilitation with testing of a wide panel of filters. The associations between ocular characteristics, subjective photosensitivity complaints, and filter choice were evaluated.
RESULTS
Photosensitivity was rated as "some" to "worst imaginable" in 77.8% of participants. Severity of photosensitivity correlated significantly with fundus hypopigmentation (p = 0.04) but not with iris translucency (p = 0.14) and it was worse in those with poor visual acuity but there was no association between photosensitivity and contrast vision. Seventy-four new pairs of spectacles were prescribed in the study. All outdoor spectacles contained a filter, whereas 26.5% of new indoor spectacles did not. Relatively neutral filter colors (gray, brown or a combination of gray and brown with other colors) and low transmission were preferred.
DISCUSSION
Photosensitivity is common in albinism, but research targeting treatment is limited. Color and neutral filters with a low light transmission were preferred, with participants having a large number of spectacles, presumably to meet their needs in different situations.
Topics: Humans; Cross-Sectional Studies; Albinism; Albinism, Oculocutaneous; Vision, Ocular; Visual Acuity
PubMed: 36028395
DOI: 10.1016/j.optom.2022.07.002 -
Ophthalmology Jun 2022To characterize the genotypic and phenotypic spectrum of foveal hypoplasia (FH). (Observational Study)
Observational Study
PURPOSE
To characterize the genotypic and phenotypic spectrum of foveal hypoplasia (FH).
DESIGN
Multicenter, observational study.
PARTICIPANTS
A total of 907 patients with a confirmed molecular diagnosis of albinism, PAX6, SLC38A8, FRMD7, AHR, or achromatopsia from 12 centers in 9 countries (n = 523) or extracted from publicly available datasets from previously reported literature (n = 384).
METHODS
Individuals with a confirmed molecular diagnosis and availability of foveal OCT scans were identified from 12 centers or from the literature between January 2011 and March 2021. A genetic diagnosis was confirmed by sequence analysis. Grading of FH was derived from OCT scans.
MAIN OUTCOME MEASURES
Grade of FH, presence or absence of photoreceptor specialization (PRS+ vs. PRS-), molecular diagnosis, and visual acuity (VA).
RESULTS
The most common genetic etiology for typical FH in our cohort was albinism (67.5%), followed by PAX6 (21.8%), SLC38A8 (6.8%), and FRMD7 (3.5%) variants. AHR variants were rare (0.4%). Atypical FH was seen in 67.4% of achromatopsia cases. Atypical FH in achromatopsia had significantly worse VA than typical FH (P < 0.0001). There was a significant difference in the spectrum of FH grades based on the molecular diagnosis (chi-square = 60.4, P < 0.0001). All SLC38A8 cases were PRS- (P = 0.003), whereas all FRMD7 cases were PRS+ (P < 0.0001). Analysis of albinism subtypes revealed a significant difference in the grade of FH (chi-square = 31.4, P < 0.0001) and VA (P = 0.0003) between oculocutaneous albinism (OCA) compared with ocular albinism (OA) and Hermansky-Pudlak syndrome (HPS). Ocular albinism and HPS demonstrated higher grades of FH and worse VA than OCA. There was a significant difference (P < 0.0001) in VA between FRMD7 variants compared with other diagnoses associated with FH.
CONCLUSIONS
We characterized the phenotypic and genotypic spectrum of FH. Atypical FH is associated with a worse prognosis than all other forms of FH. In typical FH, our data suggest that arrested retinal development occurs earlier in SLC38A8, OA, HPS, and AHR variants and later in FRMD7 variants. The defined time period of foveal developmental arrest for OCA and PAX6 variants seems to demonstrate more variability. Our findings provide mechanistic insight into disorders associated with FH and have significant prognostic and diagnostic value.
Topics: Albinism; Albinism, Ocular; Albinism, Oculocutaneous; Color Vision Defects; Cytoskeletal Proteins; Fovea Centralis; Humans; Membrane Proteins; Vision Disorders
PubMed: 35157951
DOI: 10.1016/j.ophtha.2022.02.010 -
European Journal of Pediatrics Jun 2023Oculocutaneous albinism (OCA) is a group of rare, genetic disorders caused by absent/reduced melanin biosynthesis. The aim of this study was to explore the neurovisual,...
UNLABELLED
Oculocutaneous albinism (OCA) is a group of rare, genetic disorders caused by absent/reduced melanin biosynthesis. The aim of this study was to explore the neurovisual, cognitive, adaptive, and behavioral profile of children affected by OCA, also evaluating any possible effect of the visual acuity deficit on the clinical profile and genotype-phenotype correlations. Eighteen children (9 males, mean age 84 months ± 41; range 18-181 months) with a molecular confirmed diagnosis of OCA were enrolled in the study. We collected data on clinical history, neurodevelopmental profile, neurological and neurovisual examination, and cognitive, adaptive, and emotional/behavioral functioning. A global neurodevelopmental impairment was detected in 56% of the children, without evolving into an intellectual disability. All the patients showed signs and symptoms of visual impairment. Low adaptive functioning was observed in 3 cases (17%). A risk for internalizing behavioral problems was documented in 6 cases (33%), for externalizing problems in 2 (11%), and for both in 5 (28%). Twelve children (67%) showed one or more autistic-like features. Correlation analyses revealed significant associations between the visual acuity level and performance intelligence quotient (p = 0.001), processing speed index (p = 0.021), Vineland total score (p = 0.020), Vineland communication (p = 0.020), and socialization (p = 0.037) domains. No significant correlations were found between genotype and phenotype.
CONCLUSION
Children with OCA may present a global neurodevelopmental delay that seems to improve with age and emotional/behavioral difficulties, along with the well-known visual impairment. An early neuropsychiatric evaluation and habilitative training are recommended to improve vision-related performance, neurodevelopment, and any psychological difficulties.
WHAT IS KNOWN
• Children with oculocutaneous albinism show dermatological and ophthalmological problems. • An early visual impairment may have negative implications on motor, emotional, and cognitive processes that would allow the child to organize his or her experiences.
WHAT IS NEW
• In addition to a variable combination of ocular signs and symptoms, children with oculocutaneous albinism may present an early neurodevelopmental delay and emotional/behavioral difficulties. • An early visual treatment is recommended to improve vision-related performance, neurodevelopment, and any psychological difficulties.
Topics: Male; Female; Humans; Albinism, Oculocutaneous; Visual Acuity; Genetic Association Studies; Emotions; Vision Disorders
PubMed: 37009951
DOI: 10.1007/s00431-023-04938-w -
Indian Journal of Ophthalmology Apr 2018
Topics: Albinism, Ocular; Chromosomes, Human, Pair 13; Eye Proteins; Female; Fluorescein Angiography; Fundus Oculi; Germ-Line Mutation; Humans; Infant; Membrane Glycoproteins; Retinal Detachment; Retinal Neoplasms; Retinoblastoma; Retinoblastoma Binding Proteins; Ubiquitin-Protein Ligases
PubMed: 29582825
DOI: 10.4103/ijo.IJO_1003_17 -
Genes Mar 2021Albinism encompasses a group of hereditary disorders characterized by reduced or absent ocular pigment and variable skin and/or hair involvement, with syndromic forms...
Albinism encompasses a group of hereditary disorders characterized by reduced or absent ocular pigment and variable skin and/or hair involvement, with syndromic forms such as Hermansky-Pudlak syndrome and Chédiak-Higashi syndrome. Autosomal recessive oculocutaneous albinism (OCA) is phenotypically and genetically heterogenous (associated with seven genes). X-linked ocular albinism (OA) is associated with only one gene, . We report the clinical and genetic outcomes of 44 patients, from 40 unrelated families of diverse ethnicities, with query albinism presenting to the ocular genetics service at Moorfields Eye Hospital NHS Foundation Trust between November 2017 and October 2019. Thirty-six were children (≤ 16 years) with a median age of 31 months (range 2-186), and eight adults with a median age of 33 years (range 17-39); 52.3% ( = 23) were male. Genetic testing using whole genome sequencing (WGS, = 9) or a targeted gene panel ( = 31) gave an overall diagnostic rate of 42.5% (44.4% (4/9) with WGS and 41.9% (13/31) with panel testing). Seventeen families had confirmed mutations in ( = 9), , ( = 4), ( = 1), ( = 1), ( = 1), and ( = 1). Molecular diagnosis of albinism remains challenging due to factors such as missing heritability. Differential diagnoses must include -associated foveal hypoplasia and syndromic forms of albinism.
Topics: Adolescent; Adult; Albinism, Ocular; Albinism, Oculocutaneous; Child; Child, Preschool; Diagnosis, Differential; Female; Genetic Testing; Humans; Infant; Male; Mutation; Pedigree; Phenotype; Prospective Studies; Whole Genome Sequencing; Young Adult
PubMed: 33808351
DOI: 10.3390/genes12040508 -
Investigative Ophthalmology & Visual... Jan 2022The purpose of this study was to further expand the mutational spectrum of the Foveal Hypoplasia, Optic Nerve Decussation defect, and Anterior segment abnormalities... (Comparative Study)
Comparative Study
PURPOSE
The purpose of this study was to further expand the mutational spectrum of the Foveal Hypoplasia, Optic Nerve Decussation defect, and Anterior segment abnormalities (FHONDA syndrome), to describe the phenotypic spectrum, and to compare it to albinism.
SUBJECTS AND METHODS
We retrospectively collected molecular, ophthalmic, and electrophysiological data of 28 patients molecularly confirmed with FHONDA from the Netherlands (9), Israel (13), France (2), and the United States of America (4). We compared the data to that of 133 Dutch patients with the 3 most common types of albinism in the Netherlands: oculocutaneous albinism type 1 (49), type 2 (41), and ocular albinism (43).
RESULTS
Patients with FHONDA had a total of 15 different mutations in SLC38A8, of which 6 were novel. Excluding missing data, all patients had moderate to severe visual impairment (median visual acuity [VA] = 0.7 logMAR, interquartile range [IQR] = 0.6-0.8), nystagmus (28/28), and grade 4 foveal hypoplasia (17/17). Misrouting was present in all nine tested patients. None of the patients had any signs of hypopigmentation of skin and hair. VA in albinism was better (median = 0.5 logMAR, IQR = 0.3-0.7, P 0.006) and the phenotypes were more variable: 14 of 132 without nystagmus, foveal hypoplasia grades 1 to 4, and misrouting absent in 16 of 74.
CONCLUSIONS
Compared to albinism, the FHONDA syndrome appears to have a more narrow phenotypic spectrum, consisting of nonprogressive moderately to severely reduced VA, nystagmus, severe foveal hypoplasia, and misrouting. The co-occurrence of nystagmus, foveal hypoplasia, and misrouting in the absence of hypopigmentation implies that these abnormalities are not caused by lack of melanin, which has important implications for understanding the pathogenesis of these features.
Topics: Adolescent; Adult; Aged; Albinism, Oculocutaneous; Amino Acid Transport Systems, Neutral; Anterior Eye Segment; Child; Child, Preschool; DNA; DNA Mutational Analysis; Female; Follow-Up Studies; Fovea Centralis; Humans; Infant; Male; Middle Aged; Mutation; Phenotype; Retrospective Studies; Syndrome; Visual Acuity; Young Adult
PubMed: 35029636
DOI: 10.1167/iovs.63.1.19