OBJECTIVE: To investigate the genetic etiology, clinical diagnosis and treatment of a child with pancytopenia, failure to thrive and pulmonary infection. METHODS: Peripheral blood samples of the child and her parents were collected. Genomic DNA was extracted. Genetic variants associated with hematological diseases were detected by high-throughput sequencing. RESULTS: Three variants of TCN2 gene were found, one of which located in exon 5 upstream(c.581-8A>T), the parents has carried this variant; one in exon 6 (c.924_927del), the variant was originated from the mother; one in exon 7 (c.973C>T), the variant has ocurred de novo. The variants pathogenic analysis combined with clinical manifestation, pancytopenia, the increase in methylmalonic acid level and increased homocysteine, the child was diagnosed with transcobalaminIIdeficiency. The patient presented with respiratory infection, which was confirmed to be pneumocystosis by lung radioscopy and pathogenic high-throughput sequencing of broncho-alveolar lavage fluid. The patient presented with acute respiratory distress syndrome during the treatment with intramuscular injection of vitamin B CONCLUSION We reported a case of Chinese child with TCNII deficiency due to novel gene variant, and analyzed the pathogenicity of the three variants. The treatment of TCNII deficiency with cobalamin should be individualized.
Amino Acid Metabolism, Inborn Errors ; Child ; Female ; Genetic Testing ; Humans ; Rare Diseases ; Transcobalamins/genetics* ; Vitamin B 12

OBJECTIVETo assess the association of transcobalamine II (TCN2) gene polymorphisms and serum levels of homocysteine (Hcy), vitamin Band folate with ulcerative colitis (UC) among Chinese patients.

METHODSFor 397 UC patients and 574 controls, two single nucleotide polymorphisms of the TCN2 gene (rs1801198, rs9606756) were tested with an improved multiple ligase detection reaction method. Serum Hcy, vitamin Band folate were measured with an enzymatic cycling assay and an chemiluminescence immunoassay, respectively.

RESULTSThe allelic and genotypic frequencies of rs1801198 and rs9606756 did not differ significantly between the two groups (all P> 0.05). Compared with those of the control group, the frequencies of G allele and CG+GG genotype of rs1801198 were greater in patients with moderate and severe UC (both P< 0.05). The same conclusion may also be drawn for the G allele and AG genotype of rs9606756 (both P< 0.05). Compared with the controls, average Hcy level was enhanced in UC patients (P< 0.01), whereas average vitamin Band folate levels were decreased in UC patients (both P< 0.01). In both groups, the average level of Hcy was lower in individuals carrying CC of (rs1801198) than in those with CG+GG (both P< 0.05). A similar conclusion was also drawn for individuals with AA of rs9606756 when compared with those carrying AG(both P< 0.05). Compared with patients with mild UC, average Hcy level was increased in those with moderate and severe UC (P< 0.01), while average vitamin Band folate levels were decreased in those with moderate and severe UC (both P< 0.01). The prevalence of hyperhomocysteinemia(HHcy), vitamin Bdeficiency and folate deficiency was greater in UC patients than in controls (all P< 0.01). In UC patients, the level of Hcy was negatively correlated with those of vitamin B(P< 0.01), albumin(P< 0.01), red blood cells(P< 0.01) and platelet (P< 0.05), but positively correlated with white blood cells(P< 0.01) and Mayo score (P< 0.01). Both HHcy and folate deficiency were independent risk factors for UC (OR=4.173, OR=5.206, both P< 0.01).

CONCLUSIONTCN2 (rs1801198, rs9606756) variations, as well as serum levels of Hcy, vitamin Band folate, are correlated with UC. Both HHcy and folate deficiency are independent risk factors for UC.

Adult ; Colitis, Ulcerative ; blood ; etiology ; genetics ; Female ; Folic Acid ; blood ; Genotype ; Homocysteine ; blood ; Humans ; Male ; Middle Aged ; Polymorphism, Single Nucleotide ; Transcobalamins ; genetics ; Vitamin B 12 ; blood

OBJECTIVETo investigate the association of the polymorphisms of methionine metabolism genes and the phenotype of X-linked adrenoleukodystrophy (X-ALD) and clinical severity.

METHODSThe clinical information of 120 X-ALD patients were analyzed and three genetic variants involved in the methionine metabolism, including cystathionine beta-synthase (CBS) c.844_855ins68, 5-methyltetrahydrofolate-homocysteine-S-methyltransferase (MTR) c.2756A to G, and transcobalamin 2 (TC2) c.776 C to G were analyzed by polymerase chain reaction and sequencing. The association between these polymorphisms and phenotype of X-ALD was studied.

RESULTSThe frequency of GG genotype of the TC2 c.776 C/G was higher in patients with central nervous system(CNS) demyelination than in controls (P= 0.012). However, the other two polymorphisms did not show any significant associations with the phenotypes.

CONCLUSIONThe GG genotype of TC2 c.776 C/G may contribute to X-ALD phenotype.

5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase ; genetics ; Adrenoleukodystrophy ; genetics ; Cystathionine beta-Synthase ; genetics ; Gene Frequency ; Genotype ; Humans ; Male ; Methionine ; metabolism ; Phenotype ; Polymorphism, Genetic ; Transcobalamins ; genetics

To date, the determination of serum vitamin B12 levels has been the most common laboratory test for the assessment of vitamin B12 status; however, the diagnostic accuracy of this test is low. To obtain a more sensitive marker, a new test to measure holotranscobalamin (holoTC) levels has been introduced. In this study, we assessed 45 patients for whom a vitamin B12 test had been requested and 139 anemic patients. We investigated the associations between the levels of homocysteine (Hcy) and those of holoTC, serum vitamin B12, and folate and assessed the diagnostic value of holoTC levels as a marker for vitamin B12 deficiency. We also determined the precision of the AxSYM holoTC assay by calculating the coefficient of variance (CV). The within-run and between-run precision values were excellent, as all CV values were less than 3.5%. The holoTC levels were low (<35 pmol/L) in 7 samples, and 6 of these samples had normal total serum vitamin B12 levels. In 2 of these samples, high Hcy levels (>12 micromol/L) indicated vitamin B12 deficiency. Thus, the holoTC levels were more sensitive than the serum vitamin B12 levels for indicating vitamin B12 status. If the serum vitamin B12 level is 151-300 pmol/L, the levels of holoTC alone or in combination with serum vitamin B12 levels are likely to be more useful markers than serum vitamin B12 levels alone.
Adult ; Aged ; Aged, 80 and over ; Analysis of Variance ; Biological Markers/blood ; Female ; Folic Acid/blood ; Homocysteine/blood ; Humans ; Male ; Middle Aged ; Transcobalamins/*analysis ; Vitamin B 12/*blood ; Vitamin B 12 Deficiency/diagnosis ; Young Adult