Objective:To investigate the clinical and genetic characteristics of peroxisome D-bifunctional protein deficiency (PDBPD) associated with HSD17B4 mutation. Methods:The clinical and genetic characteristics of 2 cases of PDBPD in August 2020, at Children′s Hospital Affiliated to Nanjing Medical University caused by HSD17B4 gene mutation were retrospectively analyzed. Results:Male proband and his sister suffered from neonatal epilepsy, psychomotor development disorders, ataxia, myasthenia, hearing impairment, and foot deformity.The very long chain fatty acids in serum were normal, and brain magnetic resonance imaging (MRI) showed bilateral cerebellar hemisphere atrophy.Electromyography suggested changes in the myoelectricity of multiple peripheral neurogenic lesions.Auditory evoked potential displayed severe bilateral sensorineural hearing loss.Exome sequencing identified compound heterozygous mutations (c.1171G > C, c.686-2A>T) in HSD17B4.The clinical diagnosis was PDBPD, aged 8 and 14 years, respectively. Conclusions:Two cases of HSD17B4 mutation-induced PDBPD were first reported in Chinese mainland, which was in line with its typical clinical manifestations.The newly discovered c. 1171G> C and c. 686-2A>T mutations enriched the HSD17B4 mutation spectrum.

Objective:To investigate the clinical and genetic features of children with Arts syndrome.Methods:The clinical features of a child with Arts syndrome diagnosed in Department of Neurology, Children′s Hospital of Nanjing Medical University were retrospectively analyzed.Relevant literatures about Arts syndromes were reviewed as well.Results:It was a 17-month-old boy with initial symptoms of hearing loss after birth, delayed motor development and early-onset hypotonia.At the age of 15 months old, the boy had respiratory failure due to pneumonia.Electromyographic suggested multiple peripheral neurogenic lesions.Visual evoked potentials were normal.Gene sequencing of PRPS1 of the boy revealed a novel hemizygous missense c. 421C>T (p.P141S) hemizygote missense mutation, and therefore, the boy was diagnosed as Arts syndrome.Motor development improved after rehabilitation treatment.Through literature review, 14 children with Arts syndrome, including 4 genotypes of missense mutations were reviewed in 4 English-published literatures.These cases had similar manifestations with the case reported in this study.Conclusions:Arts syndrome is a rare X-linked recessive inheritant disorder caused by PRPS1 mutations with complex clinical phenotypes.The novel missense mutation c. 421C>T found in this study expands the PRPS1 gene mutation profile.