Diagnostic findings and yield of investigations requested for children with developmental regression.

Abstract

Background: Childhood conditions that feature developmental regression are diverse and poorly understood. Phenotype-genotype characterisation and diagnostic yield data are needed to advance understanding of causal processes and inform clinical decision making. The objective of this study is to report childhood conditions featuring developmental regression and assess diagnostic yields of investigations. Method(s): A retrospective chart review of ninety-nine children presenting with developmental regression to an Australian tertiary paediatric genetic clinic. Result(s): Of 99 children, 31% of (N = 31) children had intellectual disability (ID), 19% (N = 19) were autistic, 39% (N = 39) were autistic with ID, and 9% (N = 9) children did not have an ID or autism diagnosis. Thirty-two percent (N = 32) of children received a new informative diagnosis, including potential phenotypic expansion of genes for developmental regression. Genomic testing provided the highest diagnostic yield (51.1%, N = 24) and was highest, 63.6% (N = 14) for children with an ID. Fifty percent (N = 3) of children without autism or ID, and fifty percent of autistic children with an ID (N = 6) received an informative genomic result. Conclusion(s): We highlight the heterogeneity of conditions featuring developmental regression and report phenotypic expansion not previously reported. The high diagnostic yield of genomic testing offers opportunities to identify causes and associations with diagnoses not previously reported to include regression.