Genome sequencing identifies monogenic causes in adults with metabolic diseases

Context: A subset of metabolic diseases is caused by rare monogenic variants. Next-generation sequencing offers a promising approach for identifying such variants, but its application in clinical diagnostics for metabolic disease is limited and the diagnostic yield is unknown. Objective: To determine the diagnostic yield of clinical genome sequencing (GS) in adults presenting with common metabolic diseases. Methods: We performed clinical GS on 560 adults seen in New York clinical practices between August 2020 and December 2023. Participants presented with hyperlipidemia/hypertriglyceridemia (HLD/HTG), pre-diabetes, Type 2 diabetes mellitus (T2DM), and/or metabolic dysfunction-associated fatty liver disease/steatohepatitis (MAFLD/MASH). Variants in a curated set of 90 genes associated with monogenic forms of these conditions were classified as Pathogenic (P), Likely Pathogenic (LP), or Variant of Uncertain Significance (VUS) using ACMG/ClinGen guidelines. P/LP variants in ACMG secondary findings (v3.1) genes were also reported with participant consent. Results: The cohort had a female-to-male ratio of 1.7, with 18.6% African American and 22.6% Latino participants. The most common enrollment diagnoses were HLD/HTG (25%), T2DM (9%), pre-diabetes (7%), and MAFLD/MASH (4%). Many participants had multiple conditions (42% with two, 12% with three). Approximately one-third had reportable variants, with 6% classified as P/LP. The most common P/LP variants were in APOB and LDLR. Conclusion: The prevalence of clinically significant (P/LP) variants related to primary metabolic disease in this cohort was 6%. An additional 5.5% of participants had P/LP variants in ACMG secondary findings genes. Future studies should refine participant selection for genome sequencing to optimize its diagnostic and clinical value.