The phenotype and genotype characteristics of 41 patients with steroid 5α-reductase type 2 deficiency / 中华内分泌代谢杂志

Objective To investigate the cliuical phenotype and the genotype of forty-one patients with steroid 5α-reductase type 2 deficiency.Methods The clinical data were collected including physical examination,medical history,laboratory test,as well as ultrasonic examination.Genomic DNA was extracted from peripheral blood leukocytes.Sanger sequencing and targeted gene captured next-generation sequencing were applied to detect the SRDSA2 gene mutation.Results All the patients are Han nationality and their ages ranged from 4 months to 11 years old.The karyotypes of 41 patients were 46,XY and all SRY genes were detected as positive.There were 26 (63％) patients manifested isolated micropenis,and the rest of fifteen patients were hypospadias associated with microphallus accounting for 37％.There were 39 patients who carried biallelic mutation.Two cases just identified one allele mutation.Sixteen gene mutation types were confirmed.Among them c.725A ＞ G (p.Tyr242Cys),c.694C ＞ G (p.His232Asp),and c.548-9T＞G are the novel gene types.The allele frequency of c.680G＞A (p.Arg227Gln) is 60％ (48/80).Conclusion The primary manifestations of patients with steroid 5α-reductase type 2 deficiency were micropenis or hypospadias accompanied with micropenis.c.680G＞A (p.Arg227Gln) is the predominantly mutation type of Chinese patient with steroid 5α-reductase type 2 deficiency.

The SLC22A5 genetic analysis in Chinese patients with systemic primary carnitine deficiency / 中华内分泌代谢杂志

Objective To investigate the clinical and biochemical metabolic features of 12 patients with systemic primary carnitine deficiency(CDSP) and to identify the SLC22A5 gene mutation types of the disease. Method The clinical and biochemical data were collected by retrospective analysis. DNA direct sequencing and multiplex ligation dependent probe amplification(MLPA)were applied for SLC22A5 gene analysis. Result Among 12 patients with CDSP, 3 cases had evident infection factors, 6 cases with convulsions, 5 cases manifested liver hypertrophy, 8 cases with hyperammonemia, and 9 cases showed myocardial damage. All CDSP patients were detected biallelic pathogenic mutation in SLC22A5 gene by direct sequencing. The gene types include IVS2+1G>T, c.3G>T(p.Met1Ile), c.760C>T(p.Arg254X), c.1400C>G(p.Ser467Cys), c.844dupc(p.Arg282fs), c.338G>A(p.Cys113Tyr), c.51C>G(p.Phe17Leu), c.659A>T(p.Glu220Val), and c.1365dupC(p.Thr456fs). c.659A>T(p.Glu220Val) and c.1365dupC(p.Thr456fs)are novel mutations. One female patient was maternal CDSP, her child had abnormal newborn screening. The allele frequency of c.760C>T(p.Arg254X) and c.1400C>G(p.Ser467Cys) were 37.5%(9/24)and 29.2%(7/24)respectively. The MLPA test results of all patients were negative. Conclusion The clinical manifestations are complex and various in patients with CDSP. Point and small InDel(insertions/deletions)mutation constitute the major alteration in SLC22A5 gene. c.1400C>G(p.Ser467Cys) might be another prevalence mutation type in Chinese CDSP patient.

Analysis of L2HGDH gene mutation in a patient with 2-hydroxyglutaric aciduria / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore pathogenic mutation in a family affected with 2-hydroxyglutaric aciduria.</p><p><b>METHODS</b>Exons of 3 candidate genes, including L2HGDH, D2HGDH and SLC25A1, were amplified with polymerase chain reaction and subjected to direct sequencing.</p><p><b>RESULTS</b>DNA sequencing has found that the proband and his affected younger brother have both carried a heterozygous mutation c.845G>A (p.R282Q) in the exon 7 of the L2HGDH gene. The same mutation was not detected in the his sister who was healthy. Pedigree analysis has confirmed that the above mutation was inherited from the mother. No mutation was detected in exons and flanking sequences of the D2HGDH and SLC25A1 genes.</p><p><b>CONCLUSION</b>Mutation of the L2HGDH gene probably underlies the 2-hydroxyglutaric aciduria in this family.</p>

Analysis of clinical phenotype and ACAT1 gene mutation in a family affected with beta-ketothiolase deficiency / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the clinical phenotype and ACAT1 gene mutation in a family affected with beta-ketothiolase deficiency (BKTD).</p><p><b>METHODS</b>Clinical features and laboratory test data were collected. The probands were monozygotic twin brothers. Genomic DNA was isolated from peripheral blood leukocytes obtained from the probands and their family members. Molecular genetic testing of the ACAT1 gene was carried out.</p><p><b>RESULTS</b>The probands have presented with fever, vomiting and severe ketoacidosis. By arterial blood gas testing, pH was determined to be 7.164, bicarbonate was 4.0 mmol/L, and urine ketone was ++++. Urinary organic acid gas chromatography-mass spectrometry analysis showed excessive excretion of 3-hydroxybutyric acid, 2-methyl-3-hydroxybutyric acid and tiglylglycine. Increased 3-hydroxybutyrylcarnitine (C4-OH), tiglylcarnitine(C5:1) and 3-hydroxyisovalerylcarnitine (C5-OH) levels. The clinical phenotype of proband's parents were both normal, but an elder sister turned out to be an affected patient. Genetic analysis has identified two heterozygous mutations [c.622C>T(p.R208X) and c.653C>T (p.S218F)] in the proband, which were respectively detected in the mother and father. The c.653C>T (p.S218F) mutation was not found among the 100 healthy controls and has not been included in the Human Gene Mutation Database(HGMD).</p><p><b>CONCLUSION</b>The primary clinical manifestations of BKTD is ketoacidosis. Urine organic acid and blood acylcarnitine analyses play an important role in the diagnosis of the disease. The compound heterozygous of ACAT1 gene mutations probably underlie the BKTD in our patient.</p>

Analysis of PCCA and PCCB gene mutations in patients with propionic acidemia / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze PCCA and PCCB gene mutations in 10 Chinese patients with propionic acidemia(PA).</p><p><b>METHODS</b>Genomic DNA was extracted from peripheral blood leukocytes. The 39 exons and flanking sequences of the PCCA and PCCB genes were amplified with polymerase chain reaction and subjected to direct DNA sequencing.</p><p><b>RESULTS</b>DNA sequencing has revealed that 7 patients have carried a PCCA gene mutation, 2 patients carried PCCB gene mutation and 1 patient carried mutations in both PCCA and PCCB genes. Ten PA mutations were confirmed, including 8 affecting the PCCA gene and 2 affecting the PCCB gene. Three PCCA mutations c.245G>A, IVS15+5del5, c.1288C>T and 2 PCCB mutations c.838insC, c.1087T>C were found for the first time.</p><p><b>CONCLUSION</b>Among Chinese patients with propionic acidemia patients, their genetic mutations are mainly found on the PCCA gene.</p>

Analysis of MUT gene mutations in a patient with isolated methylmalonic acidemia / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze the clinical features and mutation of MUT gene in a Chinese patient with isolated methylmalonic acidemia.</p><p><b>METHODS</b>The clinical characteristics and laboratory tests data were collected. Genomic DNA was extracted from peripheral blood leukocytes. The 13 exons and their flanking sequences of the MUT gene were amplified with polymerase chain reaction and subjected to direct DNA sequencing.</p><p><b>RESULTS</b>The patient has featured failure to thrive, lethargy, seizure, hypotonia, severe ketoacidosis and hyperammonemia. Tandem mass results showed reduction of multiple acylcarnitine. Urine organic acid testing showed pronounced increase in methylmalonate excretion. Homocysteine was normal. The patient showed no response to vitamin B12 treatment. The above results suggested that the patient had isolated methylmalonic acidemia. DNA sequencing analysis confirmed that the patient has carried two MUT gene mutations, c.755dupA and a novel mutation c.944dupT.</p><p><b>CONCLUSION</b>Inherited metabolic disease screening plays an important role in the diagnosis of clinical diseases. However, to confirm the results will need gene mutation analysis.</p>

Genetic analysis of ASS1, ASL and SLC25A13 in citrullinemia patients / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To detect potential mutations of Y9ASS1, ASL and SLC25A13 genes in four patients manifesting citrullinemia.</p><p><b>METHODS</b>Genomic DNA was extracted from peripheral blood leukocytes. Exons and their flanking sequences of the three genes were amplified with polymerase chain reaction and subjected to direct DNA sequencing.</p><p><b>RESULTS</b>Based on DNA sequence analysis, one case was diagnosed with argininosuccinate synthetase deficiency, and the mutation type (ASS1 gene) was c.236C>T (p.S79F) + c.431C>G (p.P144R). Two cases were diagnosed with argininosuccinic aciduria (ASL gene), and their gene mutations were c.434A>G (p.D145G) + c.1366C>T (p.R456W) and c.331C>T (p.R111W) + IVS8+2insT, respectively. A thirteen months boy who carried a heterozygous 851del4 mutation (SLC25A13 gene) was diagnosed with citrullinemia adult-onset type II.</p><p><b>CONCLUSION</b>Through analysis of relevant pathogenic genes, four patients have been diagnosed.</p>

Analysis of ornithine transcarbamylase gene mutations in three boys affected with late-onset ornithine transcarbamylase deficiency / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To identify the types of OTC gene mutations in three male patients with late onset ornithine transcarbamylase deficiency (OTCD, MIM #311250).</p><p><b>METHODS</b>Genomic DNA was extracted from peripheral blood leukocytes. The 10 exons and their flanking sequences of the OTC gene were amplified with polymerase chain reaction and subjected to direct DNA sequencing.</p><p><b>RESULTS</b>Based on DNA sequence analysis, all of the three patients have carried OTC gene mutations. Patients 1 and 2 were both hemizygous for mutation c.586G> A(p.D196N). A novel mutation c.800G> C(p.S267T) were confirmed in patient 3.</p><p><b>CONCLUSION</b>p.S267T mutation has affected the conserved amino acid motif of the OTC protein, and is therefore a pathogenic mutation.</p>