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Ophthalmic Surgery, Lasers & Imaging... Jun 2024We report a 23-year-old female patient with ophthalmic features of albinism, including refractive errors, nystagmus, depigmented fundus, and foveal hypoplasia. She...
We report a 23-year-old female patient with ophthalmic features of albinism, including refractive errors, nystagmus, depigmented fundus, and foveal hypoplasia. She presented for a rhegmatogenous retinal detachment, which was surgically reattached with no complications. Further genetic testing revealed the presence of a heterozygous pathogenic oculocutaneous albinism OCA2 gene mutation, conferring carrier status. To the best of our knowledge, this is the first reported case of typical ocular phenotype of albinism, specifically nystagmus, in a patient who is carrier for oculo-cutaneous albinism. Further research is required to expand the genotype-phenotype relationship in carriers of oculocutaneous albinism. .
Topics: Humans; Albinism, Oculocutaneous; Female; Fovea Centralis; Young Adult; Nystagmus, Pathologic; Tomography, Optical Coherence; Heterozygote; Membrane Transport Proteins; Mutation; Eye Diseases, Hereditary; Nystagmus, Congenital
PubMed: 38860972
DOI: 10.3928/23258160-20240207-03 -
BioRxiv : the Preprint Server For... May 2024Mutations in the human Ocular albinism type-1 gene are associated with abnormal retinal pigment epithelium (RPE) melanogenesis and poor binocular vision resulting from...
Mutations in the human Ocular albinism type-1 gene are associated with abnormal retinal pigment epithelium (RPE) melanogenesis and poor binocular vision resulting from misrouting of ipsilateral retinal ganglion cell (iRGC) axons to the brain. We studied the latter using wild-type (WT) and mouse eyes. At embryonic stages, the WT RPE-specific Oa1 protein signals through cAMP/Epac1-Erk2-CREB. Following CREB phosphorylation, a pCREB gradient extends from the RPE to the differentiating retinal amacrine and RGCs. In contrast to WT, the RPE and ventral ciliary-margin-zone, a niche for iRGCs, express less pCREB while their retinas have a disrupted pCREB gradient, indicating Oa1's involvement in pCREB maintenance. retinas also show hyperproliferation, enlarged nuclei, reduced differentiation, and fewer newborn amacrine and RGCs than WT retinas. Our results demonstrate that Oa1's absence leads to reduced binocular vision through a hyperproliferation-associated block in differentiation that impairs neurogenesis. This may affect iRGC axon's routing to the brain.
PubMed: 38798688
DOI: 10.1101/2024.05.14.594013 -
Ophthalmology. Retina May 2024
PubMed: 38739070
DOI: 10.1016/j.oret.2024.04.011 -
Pigment Cell & Melanoma Research May 2024Albinism is a phenotypically and genetically heterogeneous condition characterized by a variable degree of hypopigmentation and by ocular features leading to reduced...
Albinism is a phenotypically and genetically heterogeneous condition characterized by a variable degree of hypopigmentation and by ocular features leading to reduced visual acuity. Whereas numerous genotypic studies have been conducted throughout the world, very little is known about the genotypic spectrum of albinism in Africa and especially in sub-Saharan Western Africa. Here we report the analysis of all known albinism genes in a series a 23 patients originating from Mali. Four were diagnosed with OCA 1 (oculocutaneous albinism type 1), 17 with OCA 2, and two with OCA 4. OCA2 variant NM_000275.3:c.819_822delinsGGTC was most frequently encountered. Four novel variants were identified (two in TYR, two in OCA2). A deep intronic variant was found to alter splicing of the OCA2 RNA by inclusion of a pseudo exon. Of note, the OCA2 exon 7 deletion commonly found in eastern, central, and southern Africa was absent from this series. African patients with OCA 1 and OCA 4 had only been reported twice and once, respectively, in previous publications. This study constitutes the first report of the genotypic spectrum of albinism in a western sub-Saharan country.
PubMed: 38720644
DOI: 10.1111/pcmr.13175 -
Journal Francais D'ophtalmologie Jun 2024To investigate the relationship between refraction and ocular axial length in albinos.
PURPOSE
To investigate the relationship between refraction and ocular axial length in albinos.
PATIENTS AND METHODS
A cross-sectional, analytical study was carried out from June to November 2021 at the Central Hospital of Yaounde (Cameroon), which included consenting albino subjects aged over 15years. All subjects underwent visual acuity testing, axial length measurements and objective refraction under cycloplegia.
RESULTS
We included 51 albino subjects. The mean age was 26.06±9.47years, and the sex ratio was 0.5. Type 2 oculocutaneous albinism (OCA2) was predominant, representing 82.4% of cases. The mean uncorrected visual acuity was 0.93±0.25 logMAR, and the most common ametropia was myopic astigmatism (52.9%). The mean axial length was 24.65±2.54mm with extremes of 21.54 and 30.33mm. Eyes with myopia and myopic astigmatism had significantly longer axial lengths than those with hyperopic and mixed astigmatism. A strong, significant negative correlation (r=-0.93; P˂0.001) between the spherical component of the refraction and axial length was found.
CONCLUSION
The spherical component of the refraction decreases significantly with increasing axial length in albinos.
Topics: Humans; Male; Female; Refraction, Ocular; Adult; Cross-Sectional Studies; Young Adult; Adolescent; Axial Length, Eye; Middle Aged; Refractive Errors; Visual Acuity; Cameroon; Albinism; Myopia; Correlation of Data
PubMed: 38663224
DOI: 10.1016/j.jfo.2024.104189 -
Scientific Reports Mar 2024The purpose of this paper is to expand on the phenotype of oculocutaneous albinism type 7 (OCA7). We described three patients with OCA7: two from a consanguineous family...
The purpose of this paper is to expand on the phenotype of oculocutaneous albinism type 7 (OCA7). We described three patients with OCA7: two from a consanguineous family of Kurdish origin and one patient of Dutch origin. We compared them with all patients described to date in the literature. All newly described patients had severely reduced visual acuity (VA), nystagmus, hypopigmentation of the fundus, severe foveal hypoplasia, and chiasmal misrouting. None had iris translucency. All patients had normal pigmentation of skin and hair. We found one novel mutation in the Dutch patient: c.565G > A; p.(Gly189Ser). We compared our patients to the 15 described in the literature to date. All 18 patients had substantially pigmented skin and hair, very poor VA (0.4-1.3 logMAR), nystagmus, (mild) ocular hypopigmentation, foveal hypoplasia, and misrouting. Although pigmentation levels were mildly affected in OCA7, patients had a severe ocular phenotype with VA at the poorer end of the albinism spectrum, severe foveal hypoplasia, and chiasmal misrouting. OCA7 patients had a phenotype restricted to the eyes, and similar to that of X-linked ocular albinism. We therefore propose to rename the disorder in ocular albinism type 2. Unfolding the role of LRMDA in OCA7, may bring us a step closer in identifying the responsible factors for the co-occurrence of foveal hypoplasia and misrouting.
Topics: Humans; Albinism, Ocular; Albinism, Oculocutaneous; Nystagmus, Pathologic; Hypopigmentation; Retina; Mutation; Vision Disorders
PubMed: 38555393
DOI: 10.1038/s41598-024-57969-0 -
Oman Journal of Ophthalmology 2024A 48-year-old male with oculocutaneous albinism (OCA) presented with bilateral diminution of vision. Ocular examination revealed bilateral central corneal thinning,...
A 48-year-old male with oculocutaneous albinism (OCA) presented with bilateral diminution of vision. Ocular examination revealed bilateral central corneal thinning, scarring with ectasia, depigmented irides, transillumination defects, and pseudophakia. Examination of the right eye also revealed a hyperoleon, emulsified silicon oil in the vitreous cavity, and an attached retina, while the left eye had a total rhegmatogenous retinal detachment (RRD). This case describes a unique set of challenges (the presence of an ectatic scarred cornea and a hypopigmented fundus) and sodium fluorescein dye as an adjunct in the surgical management of a complex RRD. A review of literature highlighting the association of keratoconus and RRD in OCA is also presented in this report.
PubMed: 38524338
DOI: 10.4103/ojo.ojo_35_23 -
International Journal of Molecular... Mar 2024Aland island eye disease (AIED), an incomplete form of X-linked congenital stationary night blindness (CSNB2A), and X-linked cone-rod dystrophy type 3 (CORDX3) display...
Aland island eye disease (AIED), an incomplete form of X-linked congenital stationary night blindness (CSNB2A), and X-linked cone-rod dystrophy type 3 (CORDX3) display many overlapping clinical findings. They result from mutations in the gene encoding the α subunit of the Cav1.4 channel, which plays a key role in neurotransmission from rod and cone photoreceptors to bipolar cells. Case report: A 57-year-old Caucasian man who had suffered since his early childhood from nystagmus, nyctalopia, low visual acuity and high myopia in both eyes (OU) presented to expand the diagnostic process, because similar symptoms had occurred in his 2-month-old grandson. Additionally, the patient was diagnosed with protanomalous color vision deficiency, diffuse thinning, and moderate hypopigmentation of the retina. Optical coherence tomography of the macula revealed retinoschisis in the right eye and foveal hypoplasia in the left eye. Dark-adapted (DA) 3.0 flash full-field electroretinography (ffERG) amplitudes of a-waves were attenuated, and the amplitudes of b-waves were abolished, which resulted in a negative pattern of the ERG. Moreover, the light-adapted 3.0 and 3.0 flicker ffERG as well as the DA 0.01 ffERG were consistent with severely reduced responses OU. Genetic testing revealed a hemizygous form of a stop-gained mutation (c.4051C>T) in exon 35 of the gene. This pathogenic variant has so far been described in combination with a phenotype corresponding to CSNB2A and CORDX3. This report contributes to expanding the knowledge of the clinical spectrum of -related disease. Wide variability and the overlapping clinical manifestations observed within AIED and its allelic disorders may not be explained solely by the consequences of different mutations on proteins. The lack of distinct genotype-phenotype correlations indicates the presence of additional, not yet identified, disease-modifying factors.
Topics: Male; Humans; Child, Preschool; Infant; Middle Aged; Retinoschisis; Calcium Channels, L-Type; Genetic Diseases, X-Linked; Retinal Diseases; Retina; Mutation; Night Blindness; Myopia; Albinism, Ocular; Retinitis Pigmentosa; Eye Diseases, Hereditary
PubMed: 38474172
DOI: 10.3390/ijms25052928 -
Optometry and Vision Science : Official... Feb 2024Carriers of ocular albinism demonstrate signs of retinal mosaicism with unique features on fundus autofluorescence testing, which differentiate this condition from other...
SIGNIFICANCE
Carriers of ocular albinism demonstrate signs of retinal mosaicism with unique features on fundus autofluorescence testing, which differentiate this condition from other x-linked retinal disorders in carrier patients. Distinctive findings include a mud-splattered fundus with peripheral hyperpigmented streaks, which correlate with areas of hyperautofluorescence and hypoautofluorescence.
PURPOSE
This is the first reported case series of a family that demonstrates diagnostic retinal and fundus autofluorescence abnormalities related to retinal mosaicism in three sisters who were unaware they were carriers of ocular albinism type 1. Multimodal imaging, electrodiagnostic testing, and genetic testing can be used to confirm the diagnosis and differentiate this clinical presentation from other sight-threatening hereditary retinal diseases.
CASE REPORTS
Three sisters, aged 21, 17, and 13 years, were referred to determine the cause of abnormal retinal pigmentation. All presented with normal vision, and anterior segment examination was unremarkable without iris transillumination. They denied family history of ocular disease. Fundus examination of all three sisters revealed a mud-splattered pattern of pigmentation in the posterior pole and radial pigmentary streaks. Fundus autofluorescence showed a pattern of hyperautofluorescence and hypoautofluorescence corresponding to this pigmentary pattern. Spectral domain optical coherence tomography, electro-oculogram, and electroretinogram were normal in all three sisters. Genetic testing of their father, who was unaware of any disorder, tested positive for ocular albinism.
CONCLUSIONS
Ocular albinism carriers have abnormal retinal pigmentation in a characteristic pattern. Fundus autofluorescence shows a correlative pattern that can confirm carrier status of ocular albinism in individuals unaware of their status and rule out other retinal degenerations.
Topics: Humans; Albinism, Ocular; Retina; Fundus Oculi; Electroretinography; Tomography, Optical Coherence; Fluorescein Angiography
PubMed: 38408309
DOI: 10.1097/OPX.0000000000002106 -
Optometry and Vision Science : Official... Jan 2024I have been fortunate to spend portions of my career in each of private practice, industry, and academia. At some times, these occupations have dictated the research...
I have been fortunate to spend portions of my career in each of private practice, industry, and academia. At some times, these occupations have dictated the research direction, whereas, at others, curiosity has been allowed to dominate. This has resulted in multiple avenues of inquiry (some might say, too many), along which I have traveled with a rich and varied cast of collaborators, who have all taught me a great deal. The privilege of being awarded the Charles F. Prentice medal provides me an opportunity to summarize some of these activities. Beginning with an attempt to use contact lenses to solve a problem for those affected by albinism, the story shifts to addressing some of the wider deficiencies of contact lenses, in particular the consequences of their oxygen permeability and tendency to induce discomfort toward the end of the day. After briefly considering some aspects of meibomian gland function, the narrative concludes with the latest investigations of neurological links between the cornea and migraine.
Topics: Humans; Meibomian Glands; Contact Lenses; Awards and Prizes; Cornea
PubMed: 38350053
DOI: 10.1097/OPX.0000000000002086