Intellectual and developmental disabilities research centers: Fifty years of scientific accomplishments

The Brain Gene Registry: a data snapshot

Monogenic disorders account for a large proportion of population-attributable risk for neurodevelopmental disabilities. However, the data necessary to infer a causal relationship between a given genetic variant and a particular neurodevelopmental disorder is often lacking. Recognizing this scientific roadblock, 13 Intellectual and Developmental Disabilities Research Centers (IDDRCs) formed a consortium to create the Brain Gene Registry (BGR), a repository pairing clinical genetic data with phenotypic data from participants with variants in putative brain genes. Phenotypic profiles are assembled from the electronic health record (EHR) and a battery of remotely administered standardized assessments collectively referred to as the Rapid Neurobehavioral Assessment Protocol (RNAP), which include cognitive, neurologic, and neuropsychiatric assessments, as well as assessments for attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD). Co-enrollment of BGR participants in the Clinical Genome Resource's (ClinGen's) GenomeConnect enables display of variant information in ClinVar. The BGR currently contains data on 479 participants who are 55% male, 6% Asian, 6% Black or African American, 76% white, and 12% Hispanic/Latine. Over 200 genes are represented in the BGR, with 12 or more participants harboring variants in each of these genes: CACNA1A, DNMT3A, SLC6A1, SETD5, and MYT1L. More than 30% of variants are de novo and 43% are classified as variants of uncertain significance (VUSs). Mean standard scores on cognitive or developmental screens are below average for the BGR cohort. EHR data reveal developmental delay as the earliest and most common diagnosis in this sample, followed by speech and language disorders, ASD, and ADHD. BGR data has already been used to accelerate gene-disease validity curation of 36 genes evaluated by ClinGen's BGR Intellectual Disability (ID)-Autism (ASD) Gene Curation Expert Panel. In summary, the BGR is a resource for use by stakeholders interested in advancing translational research for brain genes and continues to recruit participants with clinically reported variants to establish a rich and well-characterized national resource to promote research on neurodevelopmental disorders.

Clinical variants paired with phenotype: A rich resource for brain gene curation

PURPOSE

Clinically ascertained variants are under-utilized in neurodevelopmental disorder research. We established the Brain Gene Registry (BGR) to coregister clinically identified variants in putative brain genes with participant phenotypes. Here, we report 179 genetic variants in the first 179 BGR registrants and analyze the proportion that were novel to ClinVar at the time of entry and those that were absent in other disease databases.

METHODS

From 10 academically affiliated institutions, 179 individuals with 179 variants were enrolled into the BGR. Variants were cross-referenced for previous presence in ClinVar and for presence in 6 other genetic databases.

RESULTS

Of 179 variants in 76 genes, 76 (42.5%) were novel to ClinVar, and 62 (34.6%) were absent from all databases analyzed. Of the 103 variants present in ClinVar, 37 (35.9%) were uncertain (ClinVar aggregate classification of variant of uncertain significance or conflicting classifications). For 5 variants, the aggregate ClinVar classification was inconsistent with the interpretation from the BGR site-provided classification.

CONCLUSION

A significant proportion of clinical variants that are novel or uncertain are not shared, limiting the evidence base for new gene-disease relationships. Registration of paired clinical genetic test results with phenotype has the potential to advance knowledge of the relationships between genes and neurodevelopmental disorders.

Behavioral analyses of animal models of intellectual and developmental disabilities

Intellectual and developmental disabilities (IDDs) are a common group of disorders that frequently share overlapping symptoms, including cognitive deficits, altered attention, seizures, impaired social interactions, and anxiety. The causes of these disorders are varied ranging from early prenatal/postnatal insults to genetic variants that either cause or are associated with an increased likelihood of an IDD. As many of the symptoms observed in individuals with IDDs are a manifestation of altered nervous system function resulting in altered behaviors, it should not be surprising that the field is very dependent upon in vivo model systems. This special issue of Neurobiology of Learning and Memory is focused on the methods and approaches that are being used to model and understand these disorders in mammals. While surveys by the Pew Foundation continue to find a high degree of confidence/trust in scientists by the public, several recent studies have documented issues with reproducibility in scientific publications. This special issue includes both primary research articles and review articles in which careful attention has been made to transparently report methods and use rigorous approaches to ensure reproducibility. Although there have been and will continue to be remarkable advances for treatment of subset of IDDs, it is clear that this field is still in its early stages. There is no doubt that the strategies being used to model IDDs will continue to evolve. We hope this special issue will support this evolution so that we can maintain the trust of the public and elected officials, and continue developing evidence-based approaches to new therapeutics.