Biochemical and genetic characteristics of 40 neonates with carnitine deficiency. / 40ä¾‹è‚‰ç¢±ç¼ºä¹ç—‡æ–°ç”Ÿå„¿çš„ç”ŸåŒ–å’Œé—ä¼ å­¦ç‰¹å¾.

OBJECTIVES: Primary carnitine deficiency (PCD) is a rare fatty acid metabolism disorder that can cause neonatal death. This study aims to analyze carnitine levels and detect SLC22A5 gene in newborns with carnitine deficiency, to provide a basis for early diagnosis of PCD, and to explore the relationship between carnitine in blood and SLC22A5 genotype. METHODS: A total of 40 neonates with low free carnitine (C0<10 µmol/L) in blood were the subjects of the study. SLC22A5 gene was detected by Sanger sequencing to analyze the value of carnitine, the results of gene test and their relationship. RESULTS: A total of 15 variants of SLC22A5 gene were detected, including 11 pathogenic or likely pathogenic variants and 4 variants of uncertain significance. There were 5 new mutations: c.288delG (p.G96fsX33), c.744_745insTCG (p.M258_L259insS), c.752A>G (p.Y251C), c.495 C>A (p.R165E), and c.1298T>C (p.M433T). We found 14 PCD patients including 2 homozygous mutations and 12 heterozygous mutations, 14 with 1 mutation, and 12 with no mutation among 40 children. The C0 concentration of children with SLC22A5 gene homozygous or complex heterozygous mutations was (4.95±1.62) µmol/L in the initial screening, and (3.90±1.33) µmol/L in the second screening. The C0 concentration of children with no mutation was (7.04±2.05) µmol/L in the initial screening, and (8.02±2.87) µmol/L in the second screening. There were significant differences between children with homozygous or compound heterozygous mutations and with no mutation in C0 concentration of the initial and the second screening (both P<0.05), as well as between children with truncated mutation and with untruncated mutation in C0 concentration of the initial screening (P=0.022). CONCLUSIONS: There are 5 new mutations which enriched the mutation spectrum of SLC22A5 gene. C0<5 µmol/L is highly correlated with SLC22A5 gene homozygous or compound heterozygous mutations. Children with truncated mutation may have lower C0 concentration than that with untruncated mutation in the initial screening.

[Establishment of hemophilia A patient-specific inducible pluripotent stem cells with urine cells].

OBJECTIVE To generate hemophilia A (HA) patient-specific inducible pluripotent stem cells (iPSCs) and induce endothelial differentiation. METHODS Tubular epithelial cells were isolated and cultured from the urine of HA patients. The iPSCs were generated by forced expression of Yamanaka factors (Oct4, Sox2, c-Myc and Klf4) using retroviruses and characterized by cell morphology, pluripotent marker staining and in vivo differentiation through teratoma formation. Induced endothelial differentiation of the iPSCs was achieved with the OP9 cell co-culture method. RESULTS Patient-specific iPSCs were generated from urine cells of the HA patients, which could be identified by cell morphology, pluripotent stem cell surface marker staining and in vivo differentiation of three germ layers. The teratoma experiment has confirmed that such cells could differentiate into endothelial cells expressing the endothelial-specific markers CD144, CD31 and vWF. CONCLUSION HA patient-specific iPSCs could be generated from urine cells and can differentiate into endothelial cells. This has provided a new HA disease modeling approach and may serve as an applicable autologous cell source for gene correction and cell therapy studies for HA.

[Mutation analysis of EXT genes in two pedigrees with hereditary multiple exostoses].

OBJECTIVE: To detect the underlying genetic defect in two Chinese families with hereditary multiple exostoses and provide genetic counseling. METHODS: Potential mutations in EXT1 and EXT2 genes in the probands were detected by direct sequencing of PCR-amplified exons. Suspected mutations were verified in all available family members and 200 unrelated healthy controls. RESULTS: A heterozygous frameshift mutation c.346_356delinsTAT in exon 1 of EXT1 and a heterozygous deletion mutation c.2009-2012del(TCAA) in exon 10 of EXT1 were respectively detected in affected members from the two families. The same mutations were not detected in unaffected members and 200 unrelated healthy controls. No mutations in EXT2 were detected in the two families. CONCLUSION: Two novel mutations of EXT1 have been detected in association with hereditary multiple exostoses in two Chinese families. Above results have provided a basis for genetic counseling for the two families and expanded the spectrum of EXT1 mutations.

In situ genetic correction of F8 intron 22 inversion in hemophilia A patient-specific iPSCs.

Nearly half of severe Hemophilia A (HA) cases are caused by F8 intron 22 inversion (Inv22). This 0.6-Mb inversion splits the 186-kb F8 into two parts with opposite transcription directions. The inverted 5' part (141 kb) preserves the first 22 exons that are driven by the intrinsic F8 promoter, leading to a truncated F8 transcript due to the lack of the last 627 bp coding sequence of exons 23-26. Here we describe an in situ genetic correction of Inv22 in patient-specific induced pluripotent stem cells (iPSCs). By using TALENs, the 627 bp sequence plus a polyA signal was precisely targeted at the junction of exon 22 and intron 22 via homologous recombination (HR) with high targeting efficiencies of 62.5% and 52.9%. The gene-corrected iPSCs retained a normal karyotype following removal of drug selection cassette using a Cre-LoxP system. Importantly, both F8 transcription and FVIII secretion were rescued in the candidate cell types for HA gene therapy including endothelial cells (ECs) and mesenchymal stem cells (MSCs) derived from the gene-corrected iPSCs. This is the first report of an efficient in situ genetic correction of the large inversion mutation using a strategy of targeted gene addition.