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Biomedical subjects

P K Hrynchak

Publications and source records attributed to P K Hrynchak.

3 recordsLinked to original sources

Bardet-Biedl syndrome.

This case report describes the presentation of a patient with Bardet-Biedl syndrome. Bardet-Biedl Syndrome is an autosomal recessive condition that includes retinal dystrophy, dystrophic extremities (commonly polydactyly), obesity, hypogenitalism, and renal disease. Cognitive deficit has also been considered part of the syndrome. The historically associated Laurence-Moon syndrome includes spastic paraparesis but not the obesity and polydactyly. They are now considered separate conditions. The most common feature of Bardet-Biedl syndrome is retinal dystrophy. The appearance of the retina in the condition is quite variable with typical retinitis pigmentosa being present in only a minority of cases. The associated optic atrophy can be primary in nature and might play a role in the decreased central vision. Diagnosis of the condition is important for visual prognosis and low vision management. The renal disease often goes undetected until specific radiological testing is done after diagnosis of Bardet-Biedl syndrome. This is significant in that early death often occurs in this condition because of the renal disease.

Adult↗

Visual recovery in a patient with Leber hereditary optic neuropathy and the 14484 mutation.

Leber hereditary optic neuropathy (LHON) is characterized by an acute, painless, sequentially bilateral reduction in vision that usually occurs in young men. It is a maternally inherited mitochondrial genetic disease. This case report details the chronology of the bilateral vision loss of a patient found to have LHON with a mutation at nucleotide site 14484. A spontaneous recovery of visual acuity and decrease in disability occurred without a corresponding improvement in color vision, contrast sensitivity, or pattern visual evoked potential (VEP's) over a period of 6 years. The abnormal pattern VEP's were one of the indicators of the neural damage to the spatial frequency channels of the visual system. The normal flash VEP's, as determined by the critical frequency of photic driving (CFPD), suggested that most of the fibers in the luminance channels were unaffected by LHON.

Adolescent↗

Visual and neural function in Leber's optic neuropathy.

This report details the chronology of vision loss for an 18-year-old Caucasian male with Leber's optic neuropathy. Findings of an oculo-visual assessment with auxiliary in-office tests of visual neural function, results of neurophysiological testing, and rehabilitative therapy with low vision aids are presented. The clinical characteristics of this devastating disorder are reviewed.

Adolescent↗