Clinical and mutational characteristics of oculocutaneous albinism type 7.

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.

Evident hypopigmentation without other ocular deficits in Dutch patients with oculocutaneous albinism type 4.

To describe the phenotype of Dutch patients with oculocutaneous albinism type 4 (OCA4), we collected data on pigmentation (skin, hair, and eyes), visual acuity (VA), nystagmus, foveal hypoplasia, chiasmal misrouting, and molecular analyses of nine Dutch OCA4 patients from the Bartiméus Diagnostic Center for complex visual disorders. All patients had severely reduced pigmentation of skin, hair, and eyes with iris transillumination over 360 degrees. Three unrelated OCA4 patients had normal VA, no nystagmus, no foveal hypoplasia, and no misrouting of the visual pathways. Six patients had poor visual acuity (0.6 to 1.0 logMAR), nystagmus, severe foveal hypoplasia and misrouting. We found two novel variants in the SLC45A2 gene, c.310C > T; (p.Pro104Ser), and c.1368 + 3_1368 + 9del; (p.?). OCA4 patients of this Dutch cohort all had hypopigmentation of skin, hair, and iris translucency. However, patients were either severely affected with regard to visual acuity, foveal hypoplasia, and misrouting, or visually not affected at all. We describe for the first time OCA4 patients with an evident lack of pigmentation, but normal visual acuity, normal foveal development and absence of misrouting. This implies that absence of melanin does not invariably lead to foveal hypoplasia and abnormal routing of the visual pathways.

[Functional vision disorder: timely examination pays off]. / Functionele visusklachten: tijdig onderzoek loont.

Patients with functional vision disorder (FVD) may present with poor visual acuity, visual field loss, or a combination of the two. This paper illustrates the utility of objective tests in diagnosing FVD. We use sweep visual evoked potentials and eye tracking as objective tests for visual acuity and visual field, respectively. These measurements should be made early in the diagnostic process because appropriate treatment becomes more difficult the longer the patient has been undergoing medical workups and referrals. Additionally, objective proof of better visual functions can be used as confirmation of the absence of a serious organic disorder. The results are used to convince patients and parents that vision is potentially much better than the patient experiences and to explain FVD. Consultation should preferably take place in a multidisciplinary setting with trained ophthalmologists and psychologists.

Chiasmal misrouting and foveal hypoplasia without albinism.

BACKGROUND/AIMS: To present the ophthalmological and electrophysiological characteristics of three darkly pigmented, female patients with misrouting and foveal hypoplasia. One of the patients had primary ciliary dyskinesia and situs inversus totalis (Kartagener syndrome). METHODS: Fundus photographs were taken and the angles at which the main temporal arterial branches leave the optic nerve head (ONH) were analysed. Optical coherence tomography (OCT) was performed through the presumed foveal region. Pattern onset visually evoked potentials (VEPs) (check sizes 60', 40/400 ms) were recorded and the chiasmal coefficient was calculated to detect misrouting. RESULTS: Fundus photography showed normally pigmented fundi with absence of the usual foveal hyperpigmentation, foveal avascular zone, and macular and foveal reflexes. On OCT no foveal pit was found. The VEP recordings showed the largest positive CI component over the right hemisphere for the left eye, and over the left hemisphere for the right eye, with the CI almost absent over the ipsilateral hemispheres. The differential derivations showed opposite polarity for the recordings of the two eyes. The chiasmal coefficients of all three patients were significantly indicative of misrouting (-0.99, -0.91, and -0.99, respectively). CONCLUSION: Based on the investigations in these patients the authors propose the hypothesis that foveal hypoplasia and misrouting exist as a distinct entity, and do not comprise the exclusive hallmark of albinism. The findings suggest that misrouting may exert a retrograde influence on foveal development.

Ocular features in Rubinstein-Taybi syndrome: investigation of 24 patients and review of the literature.

AIMS: To delineate the nature and frequency of ocular pathology in Rubinstein-Taybi syndrome (RTs). METHODS: Literature was searched for reports describing ocular symptoms in patients with RTs. 24 RTs patients (out of a total of 73 Dutch known RTs individuals) were selected for ophthalmological and electrophysiological examination, selection being based only on the distance between a patient's residence and the place of investigation. RESULTS: Most frequently reported eye anomalies in the literature were lacrimal duct obstruction, corneal abnormalities, congenital glaucoma, congenital cataract, and colobomata. Abnormalities of almost any eye segment have been published in case reports. Ophthalmological examination of 24 Dutch RTs patients showed a visual acuity

Microcephaly with chorioretinopathy. A report of two dominant families and three sporadic cases.

This is a report of seven new cases of microcephaly with chorioretinopathy. Three cases were sporadic and four were dominant: a father and son, and a father and daughter. Their ophthalmological, neurological, and systemic findings are discussed as are the genetics of the syndrome. Chorioretinopathy with characteristic punched-out lesions was observed in both entities. Body height emerges as a possible distinguishing feature between the dominant and recessive forms. In addition, locomotor disturbances are more frequently seen in patients with the recessive form.

Corneal endothelial permeability and aqueous humor dynamics in normal pressure glaucoma.

Corneal endothelial permeability and aqueous humor dynamics were studied in 17 non-treated normal pressure glaucoma patients in order to analyse the relevance of these parameters in the pathophysiology of this disease. Corneal endothelial permeability and aqueous humor flow were measured by fluorophotometry and aqueous outflow facility was determined by tonography. The results were compared with those of 17 healthy controls of similar age. The mean corneal endothelial permeability values and the aqueous flow and outflow facility values of the patients did not differ significantly from those of the healthy controls (P = 0.8, P = 0.2 and P = 0.5, respectively). Normal pressure glaucoma does not affect the corneal endothelial permeability. The aqueous humor dynamics are not primarily involved in the pathophysiology of normal pressure glaucoma.

The immediate effect of phenylephrine on aqueous flow in man.

Aqueous flow in normal human eyes was assessed at 1 hr intervals via fluorophotometric measurements, starting 4 hr after fluorescein instillation. The average coefficients of variation of the individual flow values were 5.3% and 8.4% for 1 hr and 1 week intervals, respectively. Aqueous flow was measured in 11 healthy volunteers after the instillation of phenylephrine. In the first hour the aqueous flow showed a significant increase: 131% +/- 72% (P less than 0.001) and in the second hour: 121% +/- 92% (P less than 0.002). Between 2 and 5 hr the average flow did not differ significantly from the flow in the untreated fellow eye. There was no marked effect of pupil dilation on aqueous flow.