ABSTRACT
OBJECTIVES: Spinocerebellar ataxia 27B due to GAA repeat expansions in the fibroblast growth factor 14 (FGF14) gene has recently been recognized as a common cause of late-onset hereditary cerebellar ataxia. Here we present the first report of this disease in the US population, characterizing its clinical manifestations, disease progression, pathological abnormalities, and response to 4-aminopyridine in a cohort of 102 patients bearing GAA repeat expansions. METHODS: We compiled a series of patients with SCA27B, recruited from 5 academic centers across the United States. Clinical manifestations and patient demographics were collected retrospectively from clinical records in an unblinded approach using a standardized form. Post-mortem analysis was done on 4 brains of patients with genetically confirmed SCA27B. RESULTS: In our cohort of 102 patients with SCA27B, we found that SCA27B was a late-onset (57 ± 12.5 years) slowly progressive ataxia with an episodic component in 51% of patients. Balance and gait impairment were almost always present at disease onset. The principal finding on post-mortem examination of 4 brain specimens was loss of Purkinje neurons that was most severe in the vermis most particularly in the anterior vermis. Similar to European populations, a high percent of patients 21/28 (75%) reported a positive treatment response with 4-aminopyridine. INTERPRETATION: Our study further estimates prevalence and further expands the clinical, imaging and pathological features of SCA27B, while looking at treatment response, disease progression, and survival in patients with this disease. Testing for SCA27B should be considered in all undiagnosed ataxia patients, especially those with episodic onset. ANN NEUROL 2024.
ABSTRACT
The number of certified genetic counselors (CGCs) in the genetic counseling workforce has increased over the past few decades as the number of training programs increases and CGCs expand into new patient-facing and non-patient-facing roles. Few studies have explored the distribution of CGCs across the United States. We sought to identify the U.S. geographical regions with the highest number of CGCs and those regions where the physical presence of CGCs is sparser. Deidentified city, state, and ZIP code information for each CGC in the United States were obtained from the American Board of Genetic Counseling (ABGC) database. A countrywide analysis of the distribution of CGCs was completed using geographic information system (GIS) mapping software. The data were organized into U.S. metropolitan or micropolitan statistical areas, if applicable, and analyzed by CGC per capita. We included a total of 4,554 data points (92.2%) in the analysis. Results showed there is one CGC for every 71,842 people nationwide. Of 3,141 total counties (or county equivalents) in the United States, 535 counties had at least one CGC (17.0%). The majority (98.7%) of CGCs live or work within metropolitan statistical areas (MSAs), which are defined by this study as geographical areas with greater than 50,000 people. Of the MSAs with a CGC, approximately half have more than one CGC per 100,000 people. These results are consistent with the overall distribution of the U.S. population. We believe that the MSAs with the most CGCs per capita are due to associations with specific institutions, that is, genetic counseling training programs, health system headquarters, or genetic laboratories. Although the present study cannot draw definite conclusions regarding direct patient care services provided by CGCs, it does provide a snapshot of current CGC distribution within the country. Knowing the distribution of CGCs provides a tool to conduct further workforce analyses to determine the number of CGCs needed to serve the U.S. population.