In the era of personalized and genomic medicine, awareness of patients with rare diseases is increasing as new approaches to diagnosis and treatment are developed. This study examined perceived barriers that families with rare diseases experience and explored possible differences between participants in Malaysia and the US. The study involved n=108 participants recruited in genetics clinic appointments at the University of Malaya Medical Center and three sites in Southern California. Participants completed a survey involving multiple choice and Likert scale items pertaining to perceived barriers in access to healthcare. Results from this study provide evidence of cultural differences in how patients experience potential barriers to receiving healthcare. The most frequently cited largest stressor in Malaysia was the knowledge of inheritance of the condition, while financial concerns were cited most frequently in the US. Similarities between participants in the two countries were also noted, such as the perception that expanding healthcare provider knowledge of rare diseases would be most beneficial. In both locations, it was also noted that travel distance to clinic was not perceived as a large stress factor. Taking these observations together, a healthcare model with a central location of providers well-versed in medical genetics is suggested. The data support a need for improving healthcare provider knowledge of rare disease and cultural sensitivity regarding genetic counseling of the inheritance of disease. Future studies exploring how these perceived stress factors are impacting families as well as different methods of educating providers are suggested by findings from the study.

Autism spectrum disorder (ASD) affects 2% of children and is characterized by impaired social and communication skills together with repetitive, stereotypic behavior. The pathophysiology of ASD is complex due to genetic and environmental heterogeneity, complicating the development of therapies and making diagnosis challenging. Growing evidence supports a role of disrupted Ca2+ signaling in ASD. I developed and applied a high-throughput fluorometric imaging plate reader (FLIPR) assay to monitor agonist-evoked Ca2+ signals in human primary skin fibroblasts. My results indicate that IP3 -mediated Ca2+ release from the endoplasmic reticulum in response to activation of purinergic receptors is significantly depressed in subjects with sporadic, as well as rare syndromic forms of ASD. This was apparent in Ca2+ signals evoked by G protein-coupled receptors and by photoreleased IP3 at the levels of both global and local elementary Ca2+ events, suggesting fundamental defects in IP3R channel activity in ASD.

Given the ubiquitous involvement of IP3R-mediated Ca2+ signaling in neuronal excitability, synaptic plasticity, gene expression and neurodevelopment, I further expanded my findings to a murine model of FXS. Activation of the IP3 cascade via plasma membrane metabotropic receptors did not reveal any Ca2+ signaling deficits in neurons from mice with the FMR1 gene deletion. Glial cells from FXS mice did not demonstrate any sizable difference in response to GPCR activation, or IP3 UV flash uncaging as compared with wild type. Finally, mouse fibroblasts from FXS mice assayed with the high-throughput screen FLIPR, analogous to what was used on the human skin fibroblasts, did not reveal any difference in the IP3-mediated Ca2+ release compared with wild type mice. These findings highlight divergence between animal models and human conditions, and show inadequacy of the murine model in studying the effect of the FMR1 gene mutation on IP3 signaling cascade.

In conclusion, my findings suggest that deficits in IP3-mediated Ca2+ signaling represent a convergent function shared across the spectrum of autistic disorders – whether caused by rare highly penetrant mutations or sporadic forms – and hold promise as a biomarker for diagnosis and novel drug discovery. This work also highlights potential pharmaceutical targets, and identifies Ca2+ screening in human skin fibroblasts as a promising technique for early detection of individuals susceptible to ASD.

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder characterized by deficits in social communication and interaction and the presence of repetitive behaviors and or restricted interests. ASD has heterogeneous genetic and environmental etiologies, but for most individuals with ASD the genetic cause is unknown. Determining the genetic factors contributing to an individual’s ASD phenotype is a goal in the clinic setting, as well as an important mechanism for understanding the broader pathology of ASD. As part of a larger research study, individuals with ASD and some family members had whole exome sequencing. For six probands with samples from both parents available, potential de novo variants were identified and assessed for their ability to contribute to the proband’s ASD phenotype. Some variants were in genes previously associated with non-syndromic ASD, and variants in common pathways across different probands were identified, including those involved in axon guidance. For an additional proband an analysis of the chromosomal region identified as a small deletion by a clinical microarray was completed to assess if sequence level information could contribute to the interpretation of this result. The analysis lessened the suspicion that this copy number variant contributed to the proband’s ASD phenotype. Future analysis of this data set, especially inherited variants, will continue to identify biological processes that affect the complex ASD phenotype. As an emerging technology in the genetics clinic and as a research tool, whole exome sequencing will contribute to our understanding of ASD and identify genetic targets for future discovery, diagnostics, and therapeutics.