Abstract
Purpose: :
To present the clinical characteristics including visual acuity (VA), retinal findings, genetic analysis and management of complications over a 30 year period in the only documented African-American family with North Carolina Macular Dystrophy (NCMD).
Methods: :
Twelve family members from a four generation pedigree were followed over 30 years. Clinical examination was documented during two different follow-up periods from 1979 to 1982 and 2005 to 2009. During this period, blood samples were drawn from eleven members for genetic analysis.
Results: :
Ten of 12 total and 9 of the 11 living family members had classic findings of NCMD that ranged from disease grade 2 (confluent foveal drusen, 8 eyes) to grade 3 (central macular caldera/staphyloma, 12 eyes). No patients had disease grade 1 (drusen-like parafoveal deposits). As one patient expired and two more were born after original follow-up, longitudinal data was available for 8 members. Two members, one with disease grade 2 and one with grade 3, developed choroidal neovascularization (CNV) and required laser treatment; one later developed non-clearing vitreous hemorrhage and underwent 25-gauge pars plana vitrectomy (PPV). The youngest member had disease grade 3 and developed exotropia and amblyopia in one eye. The median VA for unaffected members was 20/25. The family members without CNV had no significant change in VA over the 30 years.Genetic testing of three family members showed the same single nucleotide polymorphisms on alleles between the markers D6S249 and D6S1671, including D6S1717, within the Macular Dystrophy, Retinal, 1 (MCDR1) region of chromosome 6q16.
Conclusions: :
This African-American family shares similar MCDR1 genetics with at least 10 other American families with NCMD. This may be due to racial admixture that occurred among the previously described Irish-American family from North Carolina. Clinical characteristics, including retinal findings and good VA in the absence of amblyopia and CNV, are similar to those of other individuals with NCMD. PPV may be a reasonable surgical option to treat vitreous hemorrhage, which may occur as a result of CNV. The use of inter-racial genetic markers may help narrow the genetic locus and identify the gene mutation responsible for NCMD.
Keywords: macula/fovea • genetics • drusen