Dilated cardiomyopathy (DCM) is a life threatening disorder whose genetic basis is heterogeneous and mostly unknown. Five Arab-Christian-infants, ages 4-30 months from four families were diagnosed with DCM associated with mild skin, teeth and hair abnormalities. All passed away before age 3.

 

 A homozygous sequence variation creating a premature stop codon at PPP1R13L encoding the iASPP protein, was identified in three infants, and in the mother of the other two. Patients’ fibroblasts and PPP1R13L-knocked down human fibroblasts presented higher expression levels of pro-inflammatory cytokine genes in response to Lipopolysaccharide, as well as ppp1r13l-knocked down murine cardiomyocytes and hearts of ppp1r13l-deficient mice.

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 The hypersensitivity to Lipopolysaccharide was NF-κB-dependent, and its inducible binding activity to promoters of pro-inflammatory cytokine genes was elevated in patients’ fibroblasts. RNA-sequencing of ppp1r13l-knocked down murine cardiomyocytes and of hearts derived from different stages of DCM development in ppp1r13l-deficient mice revealed the crucial role of iASPP in dampening cardiac inflammatory response. Our results determined PPP1R13L as the gene underlying a novel autosomal recessive cardio cutaneous syndrome in humans, and strongly suggest that the fatal DCM during infancy is a consequence of failure to regulate transcriptional pathways necessary for tuning cardiac threshold response to common inflammatory stressors.