Abstract
Purpose :
To describe the longitudinal clinical characteristics of children with Blue Cone Monochromacy (BCM) secondary to a locus control region (LCR) deletion.
Methods :
In a retrospective study at Cincinnati Children's Hospital, children <18 years with a clinical and molecular diagnosis of BCM and LCR deletion were analyzed between January 1st, 2008, to June 30th, 2021. Clinical findings included presenting symptoms and signs, family history, best-corrected visual acuity (BCVA) in better seeing eye, age at BCM diagnosis, ancillary testing when performed (ffERG, visual field, fundus photography and autofluorescence (AF), SD-OCT), and educational interventions.
Results :
8 males from 7 families with BCM secondary to an LCR deletion presented at a median age of 2y (0.2-10.8y) with a median follow-up of 4.4y (1-11). All presented with photophobia and nystagmus, with resolution of nystagmus in 4 patients at the most recent visit (MRV). 7 patients had an individualized educational program (IEP) for low vision. BCVA was stable from initial recognition acuity to MRV, at a median of 20/125 (20/80-20/300) and 20/125 (20/100-20/200) respectively. Refractive error was common at both initial and MRV with a median spherical equivalent of +4.38D(-2.75-+6.00D), age 1y(0.17-11y) and -1.1D(+3.75—13D), age 9.5y(4-16y). Retinal changes varied among patients (Table 1). Time from initial visit to BCM diagnosis of those without a known familial diagnosis was 3.3 y (2.5-11.5y).
Conclusions :
Children with BCM secondary to LCR deletion had reduced central vision that maintained stable over follow up and was amenable to mainstream school with an IEP for vision. Significant phenotypic variability is present in children with the same LCR deletion, both in refractive error and retinal features. Further longitudinal follow-up is needed to characterize the natural history of BCM due to LCR deletions across the lifespan.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.