ABSTRACT
PURPOSE OF REVIEW: The purpose of this review is to highlight recent genetic studies of the Amish and Mennonite (Plain) communities. For decades, the study of genetically isolated populations has improved our understanding and management of genetic diseases that affect all populations. RECENT FINDINGS: Major themes of current genetic research of the Amish and Mennonites include new causative gene and new candidate gene discovery, phenotype expansion of previously identified genetic disease, and a target for AAV9-mediated gene therapy. Additionally, several genome-wide association studies (GWAS) examining complex traits such as dementia, cardiometabolic disease, and age-related macular degeneration have been conducted. Finally, clinically relevant studies of attitudes of the Plain community towards genetic testing and telemedicine, as well as reviews of and management suggestions for the Amish variants of propionic acidemia and APOB-associated familial hypercholesterolemia have been recently published. SUMMARY: Recent genetic studies of the Plain community continue to highlight the value of studying isolated populations to propel genetic disease discovery and treatment. Additionally, population-specific polygenic risk scores are needed for underrepresented and minority populations, to avoid exacerbating disparities in medical genetics care. Finally, it is important for clinicians to develop management guidelines for variants common in this rapidly growing population, such as propionic acidemia.
ABSTRACT
CALFAN syndrome is an extremely rare disease consisting of recurrent pediatric acute liver failure (PALF), neurodegenerative diseases, and skeletal abnormalities associated with SCYL1 gene mutation. To date, three of 18 patients reported underwent liver transplantation in infancy and early childhood (7-23 months). Here, we report a case of CALFAN syndrome with infantile onset, recurrent jaundice/PALF requiring liver transplantation in early adulthood. At the most recent follow-up, 3 years after transplantation, the patient is doing well.
ABSTRACT
OBJECTIVE: Temporal lobe epilepsy (TLE) patients exhibit signs of memory impairments even when seizures are pharmacologically controlled. Surprisingly, the underlying molecular mechanisms involved in TLE-associated memory impairments remain elusive. Memory consolidation requires epigenetic transcriptional regulation of genes in the hippocampus; therefore, we aimed to determine how epigenetic DNA methylation mechanisms affect learning-induced transcription of memory-permissive genes in the epileptic hippocampus. METHODS: Using the kainate rodent model of TLE and focusing on the brain-derived neurotrophic factor (Bdnf) gene as a candidate of DNA methylation-mediated transcription, we analyzed DNA methylation levels in epileptic rats following learning. After detection of aberrant DNA methylation at the Bdnf gene, we investigated functional effects of altered DNA methylation on hippocampus-dependent memory formation in our TLE rodent model. RESULTS: We found that behaviorally driven BdnfDNA methylation was associated with hippocampus-dependent memory deficits. Bisulfite sequencing revealed that decreased BdnfDNA methylation levels strongly correlated with abnormally high levels of BdnfmRNA in the epileptic hippocampus during memory consolidation. Methyl supplementation via methionine (Met) increased BdnfDNA methylation and reduced BdnfmRNA levels in the epileptic hippocampus during memory consolidation. Met administration reduced interictal spike activity, increased theta rhythm power, and reversed memory deficits in epileptic animals. The rescue effect of Met treatment on learning-induced BdnfDNA methylation, Bdnf gene expression, and hippocampus-dependent memory, were attenuated by DNA methyltransferase blockade. INTERPRETATION: Our findings suggest that manipulation of DNA methylation in the epileptic hippocampus should be considered as a viable treatment option to ameliorate memory impairments associated with TLE.