Original Article
Clinical and variant analysis of 15 patients with methylmalonic acidemia
Xiong Hui, Deng Wenlin, Guo Lanying, Shi Congcong, Xiao Xin, Hao Hu
Published 2019-12-10
Cite as Chin J Med Genet, 2019,36(12): 1158-1162. DOI: 10.3760/cma.j.issn.1003-9406.2019.12.002
Abstract
ObjectiveTo report on clinical characteristics and genetic findings in 15 Chinese patients with methylmalonic acidemia (MMA).
MethodsFor the 15 MMA patients detected by tandem mass spectrometry, genetic analysis was carried out in twelve pedigrees. Clinical characteristics, genetic finding, treatment and outcomes were retrospectively analyzed.
ResultsThe main features of the patients included poor feeding, recurrent vomiting, lethargy, seizure and development retardation. Blood propionylcarnitine (except for 3 patients), its ratio with acetylcarnitine, and urine methylmalonic acid were increased in all patients. Twelve patients were diagnosed genetically, which included 7 with MUT variants, 4 with MMACHC variants, and 1 with MMAB variant. Nine MUT variants were detected, among which c. 1159A>C, 753+ 1delGinsTGGTTATTA and c. 504del were novel. Six known pathogenic MMACHC variants and two novel MMAB variants (c.289_290delGG, c. 566G>A) were also detected. Seven patients died of metabolic crises within a year, others had improved effectively following the treatment, but had mild to severe growth delay and/or developmental retardation.
ConclusionThe clinical manifestation of MMA are complex. Most patients have variants of the MUT and MMACHC genes. High mortality may occur before one year of age.
Key words:
Organic acidemia; Methylmalonic acidemia; MUT gene; MMACHC gene; MMAB gene
Contributor Information
Xiong Hui
Department of Pediatrics, the Sixth Affiliated Hospital of Sun Yet-sen University, Guangzhou, Guangdong 510655, China
Deng Wenlin
Department of Pediatrics, the Sixth Affiliated Hospital of Sun Yet-sen University, Guangzhou, Guangdong 510655, China
Guo Lanying
Department of Pediatrics, the Sixth Affiliated Hospital of Sun Yet-sen University, Guangzhou, Guangdong 510655, China
Shi Congcong
Inborn Errors of Metabotism Laboratory, the Sixth Affiliated Hospital of Sun Yet-Sen University, Guangzhou, Guangdong 510655, China
Xiao Xin
Department of Pediatrics, the Sixth Affiliated Hospital of Sun Yet-sen University, Guangzhou, Guangdong 510655, China
Hao Hu
Department of Pediatrics, the Sixth Affiliated Hospital of Sun Yet-sen University, Guangzhou, Guangdong 510655, China