A negative waveform in the scotopic response in a patient with phosphoglycerate kinase deficiency: a visual electrophysiology report.

Purpose: Phosphoglycerate kinase (PGK) deficiency is an X-linked neurometabolic genetic disorder with variable systemic manifestations. So far, only one patient with retinal anomalies has been reported, but no visual electrophysiology findings were described. We report the first description of visual electrophysiology in a child with PGK deficiency. This provides further information for the site of involvement in the eye.

Method: A case history of a nine-year-old boy with PGK deficiency is reported.

Results: This patient was diagnosed with PGK deficiency by screening soon after birth, as his mother was a known carrier of a PGK gene mutation. A bone marrow transplant was performed at the age of 9 months. He had two episodes of encephalopathy following the transplant but no acute episode of haemolysis. From the age of 6 years, his vision has been deteriorating. Visual electrophysiology results identified retinal involvement involving both rod and cone dysfunction. The visual evoked potential was normal.

Conclusions: Retinal dystrophy may be one of the clinical manifestations of phosphoglycerate kinase deficiency.