Citations

AbstractBackgroundFrontotemporal dementia (FTD) is a collection of neurodegenerative diseases affecting behavior, cognition, and motor functions. FTD treatment trials will benefit from sensitive assessments capable of detecting and longitudinally tracking cognitive changes. Remote smartphone cognitive tests may improve the sensitivity to detect and monitor cognitive decline via novel methods of data capture and more frequent assessments within ecologically valid environments, while simultaneously reducing patient burden. The first step in determining the utility of these measures is establishing their reliability. We previously reported baseline reliability estimates for the ALLFTD Mobile App cognitive tests in a small pilot sample. Here we extend these results using a larger sample and evaluate six‐month stability.MethodWe enrolled a diagnostically mixed sample of 128 participants (CDR®+NACC‐FTLD = 0 [n = 84]; CDR®+NACC‐FTLD = 0.5 [n = 21]; CDR®+NACC‐FTLD≥1 [n = 23]) from ongoing studies of healthy aging (Hillblom Network) and frontotemporal dementia (ALLFTD). Participants self‐administered five cognitive tests from the ALLFTD Mobile App on their own smartphone; they were asked to complete each test three times within two weeks. Tests included gamified versions of N‐back, Stroop, Flanker, and Go/No‐Go paradigms, and an adaptive short‐term memory test. We evaluated the internal consistency of each test’s first occurrence using Spearman‐Brown split‐half reliability (100 simulations). Test‐retest reliability over the first three baseline replicates (as available) was evaluated by calculating intraclass correlations (ICC). In a preliminary analysis, we tested the six‐month stability of test performance in nine functionally intact participants who completed baseline and follow‐up Flanker, N‐Back, and adaptive memory assessments by calculating Spearman’s rho.ResultSplit‐half reliability estimates were in the good to excellent range (r’s: 0.81–0.97). Test‐retest reliability estimates were in the adequate to excellent range (ICCs: 0.72–0.96). ICC estimates were comparable for participants with and without clinical impairment (CDR®+NACC‐FTLD = 0 (0.74–0.95) and CDR®+NACC‐FTLD >0 (0.67–0.95). Among functionally intact individuals, baseline and 6‐months scores were highly correlated (r’s: 0.76–0.93, p’s<.05).ConclusionOur findings of adequate to excellent internal consistency, test‐retest reliability, and 6‐month stability support the feasibility of remote, smartphone‐based cognitive testing among a diagnostically mixed sample typical of healthy aging and frontotemporal dementia research studies.

AbstractBackgroundRemote digital cognitive assessments validated for use in frontotemporal dementia (FTD) and other neurodegenerative diseases would benefit clinical trials and clinical care. The ALLFTD Mobile App includes several smartphone‐based measures of cognition, and prior studies have provided preliminary support for their reliability. Here we evaluate their validity by testing associations with gold standard clinical outcomes and expected neural correlates.MethodA diagnostically mixed sample of 92 participants (CDR®+NACC‐FTLD = 0 [n = 33]; CDR®+NACC‐FTLD = 0.5 [n = 15]; CDR®+NACC‐FTLD≥1 [n = 16]; unknown [n = 28]) were recruited from a UCSF healthy aging study (Hillblom Network) and a North American FTD study (ALLFTD). Participants were asked to remotely complete four ALLFTD Mobile App tests of executive functioning (EF) and a memory test on their smartphones. Gold standard clinical measures were also collected; outcomes were the UDSv3 EF composite, CVLT‐SF Total Immediate Recall (memory), and CDR®+NACC‐FTLD Box Score (disease severity). Volumetric brain MRI measurements were available for a subset (n = 37). Expected neural correlates were frontoparietal gray matter volume for EF tests and hippocampal volume for the memory test. Linear models were fitted to evaluate the association of app tests with the gold standard outcomes, controlling for education, sex, and total intracranial volume (imaging only).ResultSmartphone EF measures were strongly and positively associated with the UDS3‐EF composite (ß’s = 0.6–0.8, all p<.001). The memory test was strongly correlated with the CVLT‐SF (ß = 0.7, p<.001). Tests were less strongly associated with divergent cognitive domains (e.g., associations with a visuospatial test were ß’s = 0.1–0.3). Worse performance on all tests was significantly associated with greater disease severity (ß’s = 0.5–0.7, all p<.001). Worse app‐based EF scores were associated with lower frontoparietal volume (ß’s = 0.4–0.6, all p<.015) and worse memory scores with lower hippocampal volume (ß = 0.5, p<.001).ConclusionALLFTD Mobile App scores were strongly associated with gold standard neuropsychological tests of the same cognitive domain (i.e., convergent validity) and less associated with measures of a different domain (i.e., divergent validity). Worse performance on the smartphone tests was associated with increasing disease severity and volume loss in expected brain regions. These results provide preliminary support for the construct validity of the ALLFTD Mobile App cognitive tests.

Abstract The blood–brain barrier ensures CNS homeostasis and protection from injury. Claudin-5 (CLDN5), an important component of tight junctions, is critical for the integrity of the blood–brain barrier. We have identified de novo heterozygous missense variants in CLDN5 in 15 unrelated patients who presented with a shared constellation of features including developmental delay, seizures (primarily infantile onset focal epilepsy), microcephaly and a recognizable pattern of pontine atrophy and brain calcifications. All variants clustered in one subregion/domain of the CLDN5 gene and the recurrent variants demonstrate genotype–phenotype correlations. We modelled both patient variants and loss of function alleles in the zebrafish to show that the variants analogous to those in patients probably result in a novel aberrant function in CLDN5. In total, human patient and zebrafish data provide parallel evidence that pathogenic sequence variants in CLDN5 cause a novel neurodevelopmental disorder involving disruption of the blood–brain barrier and impaired neuronal function.

Abstract Multiple myeloma (MM) develops from well-defined precursor stages; however, invasive bone marrow (BM) biopsy limits screening and monitoring strategies for patients. We enumerated circulating tumor cells (CTC) from 261 patients (84 monoclonal gammopathy of undetermined significance, 155 smoldering multiple myeloma, and 22 MM), with neoplastic cells detected in 84%. We developed a novel approach, MinimuMM-seq, which enables the detection of translocations and copy-number abnormalities through whole-genome sequencing of highly pure CTCs. Application to CTCs in a cohort of 51 patients, 24 with paired BM, was able to detect 100% of clinically reported BM biopsy events and could replace molecular cytogenetics for diagnostic yield and risk classification. Longitudinal sampling of CTCs in 8 patients revealed major clones could be tracked in the blood, with clonal evolution and shifting dynamics of subclones over time. Our findings provide proof of concept that CTC detection and genomic profiling could be used clinically for monitoring and managing disease in MM. Significance: In this study, we established an approach enabling the enumeration and sequencing of CTCs to replace standard molecular cytogenetics. CTCs harbored the same pathognomonic MM abnormalities as BM plasma cells. Longitudinal sampling of serial CTCs was able to track clonal dynamics over time and detect the emergence of high-risk genetic subclones. This article is highlighted in the In This Issue feature, p. 247

PURPOSE Diagnosis of Mismatch Repair Deficiency (MMRD) is crucial for tumor management and early detection in patients with the cancer predisposition syndrome constitutional mismatch repair deficiency (CMMRD). Current diagnostic tools are cumbersome and inconsistent both in childhood cancers and in determining germline MMRD. PATIENTS AND METHODS We developed and analyzed a functional Low-pass Genomic Instability Characterization (LOGIC) assay to detect MMRD. The diagnostic performance of LOGIC was compared with that of current established assays including tumor mutational burden, immunohistochemistry, and the microsatellite instability panel. LOGIC was then applied to various normal tissues of patients with CMMRD with comprehensive clinical data including age of cancer presentation. RESULTS Overall, LOGIC was 100% sensitive and specific in detecting MMRD in childhood cancers (N = 376). It was more sensitive than the microsatellite instability panel (14%, P = 4.3 × 10 −12 ), immunohistochemistry (86%, P = 4.6 × 10 −3 ), or tumor mutational burden (80%, P = 9.1 × 10 −4 ). LOGIC was able to distinguish CMMRD from other cancer predisposition syndromes using blood and saliva DNA ( P < .0001, n = 277). In normal cells, MMRDness scores differed between tissues (GI > blood > brain), increased over time in the same individual, and revealed genotype-phenotype associations within the mismatch repair genes. Importantly, increased MMRDness score was associated with younger age of first cancer presentation in individuals with CMMRD ( P = 2.2 × 10 −5 ). CONCLUSION LOGIC was a robust tool for the diagnosis of MMRD in multiple cancer types and in normal tissues. LOGIC may inform therapeutic cancer decisions, provide rapid diagnosis of germline MMRD, and support tailored surveillance for individuals with CMMRD.