Clinical characteristics and genetic analysis of six children with carnitine palmitoyltransferase 2 deficiency
Objective:To investigate the clinical characteristic and genetic variants of children with carnitine palmitoyltransferase 2(CPT2)deficiency.Methods:The clinical and genetic data of 6 children with CPT2 deficiency were retrospectively analyzed.The blood acylcarnitines and genetic variants were detected with tandem mass spectrometry and whole-exon gene sequencing,respectively.Results:There were 4 males and 2 females with a mean age of 32 months(15 d-9 years)at diagnosis.One case was asymptomatic and with normal laboratory test results,2 had delayed onset,and 3 were of infantile type.Three cases were diagnosed at neonatal screening,and 3 cases presented with clinical manifestations of fever,muscle weakness,and increased muscle enzymes.Five children presented with decreased free carnitine and elevated levels of palmitoyl and octadecenoyl carnitines.CPT2 gene variants were detected at 8 loci in 6 children(4 harboring biallelic mutations and 2 harboring single locus mutations),including 3 known variants(p.R631C,p.T589M,and p.D255G)and 5 newly reported variants(p.F352L,p.R498L,p.F434S,p.A515P,and c.153-2A>G).It was predicted by PolyPhen2 and SIFT software that c.153-2A>G and p.F352L were suspected pathogenic variants,while p.R498L,p.F434S and p.A515P were variants of unknown clinical significance.Conclusions:The clinical phenotypes of CPT2 deficiency are diverse.An early diagnosis can be facilitated by neonatal blood tandem mass spectrometry screening and genetic testing,and most patients have good prognosis after a timely diagnosis and treatment.
Carnitine palmitoyltransferase 2 deficiencyClinical featuresCPT2 geneTandem mass spectrometryFree carnitineCase report