The clinical features, examination findings and genetic testing results of a newborn with neurobehavioral developmental abnormality caused by the PAK3 gene mutation in the Department of Neonatology, Anhui Provincial Children′s Hospital were retrospectively analyzed in November 11, 2021.The male 9-day-old newborn presented with the difficult-to-wean for 9 days after birth.The child had repeated startle reflexes, decreased muscle tension in the extremities, and partial primitive reflexes.Amplitude-integrated electroencephalogram (aEEG) showed the lower and upper boundary voltage of 10 μV and 40 μV, respectively.Obvious mature sleep-wake cycles were not found, and 2 electric seizures were recorded.The aEEG suggested the moderate-to-severe abnormal aEEG.Magnetic resonance imaging showed that the corpus callosum was slightly thinner.The family-centered diagnostic exosome sequencing showed a missense mutation of the PAK3 gene[c.1327 (exon18) G>A, p.G443R], which has not been previously reported at home and abroad.This case enriched the clinical phenotype of the PAK3 gene mutation and suggested the potential value of whole genome sequencing in clinical diagnosis and genetic guidance.