Context PLIN1 encodes Perilipin-1 which coats lipid droplets in adipocytes and is involved in droplet formation, triglyceride storage and lipolysis. Rare PLIN1 frameshift variants that extend the translated protein have been described to cause lipodystrophy. Objective To test whether PLIN1 protein-truncating variants cause lipodystrophy in a large population-based cohort. Design We identified individuals with PLIN1 PTVs in individuals with exome data in UK Biobank. We performed gene-burden testing for individuals with PLIN1 PTVs. We replicated the associations using data from the T2D Knowledge portal. We performed a phenome-wide association study using publicly available association statistics. Setting A population-based cohort and a T2D case/control study. Participants 362,791 individuals in UK Biobank and 43,125 individuals in the T2D Knowledge portal. Main Outcome Measures: Twenty-two diseases and traits relevant to lipodystrophy. Results The 735 individuals with PLIN1 protein-truncating variants had a favourable metabolic profile. These individuals had increased HDL cholesterol (0.12mmol/L, 95% CI: 0.09, 0.14, P=2x10 -18), reduced triglycerides (-0.22 mmol/L 95% CI: -0.29, -0.14, P=3x10 -11), reduced waist hip ratio (-0.02, 95% CI: -0.02, -0.01, P=9x10 -12) and reduced systolic blood pressure (-1.67 mmHg, -3.25, -0.09, P=0.05). These associations were consistent in the smaller T2D knowledge portal cohort. In UK Biobank, PLIN1 PTVs were associated with reduced risk of myocardial infarction (OR=0.59, 95% CI: 0.35, 0.93, P=0.02) and hypertension (OR=0.85, 95% CI: 0.73, 0.98, P=0.03), but not Type 2 diabetes (OR=0.99 95% CI: 0.63,1.51, P=0.99). Conclusion Our study suggests that PLIN1 haploinsufficiency causes a favourable metabolic profile and may protect against cardiovascular disease.

Pyruvate kinase deficiency anaemia was suspected in an 18-month-old male Basenji dog after other known causes of canine haemolytic anaemia had been excluded. Anaemia of moderate severity (packed cell volumes 0.20 to 0.26 1/1) and reticulocytosis (uncorrected reticulocyte counts 8 to 43%) persisted during 5 months' observation, and biopsies showed development of bone marrow fibrosis and sclerosis. The diagnosis of pyruvate kinase deficiency anaemia was presumptive because erythrocyte pyruvate kinase concentrations in the affected dog were inconclusive and related animals were not available for enzyme assay. However, the gene for pyruvate kinase deficiency is known to occur among Basenji dogs in Australia.