AUTHOR=Shu Jianbo , Zhi Xiufang , Chen Jing , Lei Meifang , Zheng Jie , Sheng Wenchao , Zhang Chunhua , Li Dong , Cai Chunquan 

TITLE=Case Report: A Case of β-Ureidopropionase Deficiency Complicated With MELAS Syndrome Caused by UPB1 Variant and Mitochondrial Gene Variant

JOURNAL=Frontiers in Pediatrics

VOLUME=Volume 10 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/pediatrics/articles/10.3389/fped.2022.838341

DOI=10.3389/fped.2022.838341

ISSN=2296-2360

ABSTRACT=Background: β-ureidopropionase deficiency is a rare autosomal recessive disease affecting the last step of pyrimidine degradation and Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes syndrome is a rare inherited disorder caused by genetic defects in mitochondrial DNA.
Case presentation: A 8-year-old boy presented with dizziness, vomiting and convulsions. The gas chromatography-mass spectrometry showed β-ureidopropionase deficiency. Analysis of whole exome sequencing detected homozygous missense variant c.977G>A (p.R326Q) in UPB1. But the patient had persistent hyperlactacidemia and metabolic acidosis, which was not consistent with the classic features of β-ureidopropionase deficiency, combined with the manifestations of developmental delay, poor academic performance and poor sports stamina, so the mitochondrial DNA genetic analysis was performed. The results indicated the mutation m.3243A>G of MT-TL1 gene. The heteroplasmy level was 65% and that of patient’s mother was 17.8%. Eventually, the ultimate diagnosis of β-ureidopropionase deficiency combined with MELAS syndrome was established.
Conclusions: The report about β-ureidopropionase deficiency caused by nuclear gene variation and MELAS syndrome caused by mitochondrial gene variant coexisting in the same patient enriches the clinical study of these two rare diseases.