A zebrafish model of nicotinamide adenine dinucleotide (NAD+) deficiency-derived congenital disorders.

Developmental NAD+ deficiency is associated with diverse congenital malformations. Congenital NAD deficiency disorder (CNDD) is a multisystem developmental condition characterized by cardiac, renal, vertebral, and limb anomalies, among others. It is caused by biallelic pathogenic variants in genes involved in the nicotinamide adenine dinucleotide (NAD+) synthesis pathway. CNDD anomalies overlap with clinical features described in vertebral-anal-cardiac-tracheoesophageal fistula-renal-limb (VACTERL) association, suggesting a possible shared etiological link through NAD+ deficiency. However, the aberrant developmental mechanisms of NAD+-deficient congenital anomalies remain poorly understood. To dynamically explore NAD+-deficiency-induced congenital malformations, we developed a zebrafish model of NAD+ disruption. Zebrafish embryos treated with 2-amino-1,3,4-thiadiazole (ATDA), a known NAD+ metabolism disruptor, exhibited cardiac, tail, spinal cord, and craniofacial defects, which were partially rescued by nicotinamide (NAM) in a dose-dependent manner. Our work establishes zebrafish as a useful model for investigating how NAD+ deficiency contributes to multisystem congenital anomalies.