Clinical and genetic analysis of 14 cases with 21-hydroxylase deficiency / 中华实用儿科临床杂志

Objective To analyze the correlation of clinical phenotype and genotype and gene mutation frequency characteristics of 21-hydroxylase deficiency,and to provide the basis for clinical diagnosis and methods for early intervention.Methods The clinical phenotypic signs and examination results of 14 cases with 21-hydroxylase deficiency were collected from September 2008 to December 2016 in Children's Hospital of Shanxi Province.Point mutations,deletions and conversion mutations for gene CYP21A2 coding 21-hydroxylase were detected through using next generation sequencing(NGS) and multiplex ligation-dependent probe amplification (MLPA).The captured mutations were further confirmed with Sanger sequencing.Furthermore,the family members underwent the co-segregation validation through the Sanger sequencing or MLPA in those captured mutated sites.Results Among the total 14 cases,9 cases were identified as the salt wasting,5 cases the simple virilizing;10 cases of compound heterozygous mutations,and 4 cases of homozygous mutations.Analysis of the 14 patients revealed 8 different kinds of mutations in CYP21A2 gene.The most frequent mutations of CYP21A2 gene were I2G [50％ (14/28)] and I173N [21.4％ (6/28)],followed by Arg357Trp[10.7％ (3/28)].Del[10.7％ (3/28)] mutations including E247fs,Gly1 1 1fs and R484fs.Q319X [3.6％ (1/28)] and Arg355His[3.6％ (1/28)] were rarely found.Missense mutation was found in 10 cases,splicing mutation in 14 cases,frameshifi mutations in 3 cases,nonsense mutations in 1 case.All of the mutations were inherited from their parents,and no new mutation was found.The most common mutations for salt wasting and simple virilizing were respectively I2G[50％ (9/18)] and I173N [50％ (5/10)].Collectively,genotypes and phenotypes were matched with each other.Conclusions The combination of clinical phenotypes with laboratory examination by gene sequencing and comprehensive analysis,is helpful to early diagnosis,differential diagnosis and optimized treatment,which will improve prognosis and provide guidance for genetic consultancy.

Novel multiplex primer extension and denaturing high-performance liquid chromatography for genotyping of the deafness gene mutations / 中南大学学报(医学版)

To find a rapid and accurate genotyping method for specific non-syndromic hearing loss (NSHL)-causing gene mutations for disease diagnosis in different ethnic populations.Methods We performed a novel multiplex primer extension (PE) reaction in combination with denaturing high-performance liquid chromatography (DHPLC) to simultaneously detect and genotype the 6 most common mutations in 180 patients with NSHL (GJB2-235delC,GJB2-299delAT,PDS-A2168G,PDS IVS7-2A ＞ G,mtDNA-A1555G,and mtDNA-C1494T) in Chinese population.This method involved the amplification of the target sequence,followed by a purification step,a multiplex PE reaction,and DHPLC analysis performed on the Transgenomic Wave DNA fragment analysis system under fully-denaturing conditions.Results In a blind analysis,this technique successfully and accurately genotyped 100％ of the samples simultaneously characterized by direct sequencing.Conclusion Combination of PE and DHPLC is simple,rapid,accurate,and cost-effective for genotyping common disease-causing mutations,including substitutions,insertions,and deletions in NSHL,and may be successfully used in other genetic diseases.

Identification of the small supernumerary marker chromosomes in two patients with Turner syndrome / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To identify the small supernumerary marker chromosomes (sSMC) and guide the genetic counseling and medical treatment in two patients with Turner syndrome.</p><p><b>METHODS</b>High resolution GTG and C banding, SRY amplification by PCR and fluorescence in situ hybridization (FISH) on metaphase chromosomes were performed to the two patients.</p><p><b>RESULTS</b>The karyotypes of the two patients were 45, X [29]/46,X, +mar[31] and 45,X[71]/46,X, +mar[29] respectively. SRY test indicated SRY-positive for patient 1, whose sSMC was originated from chromosome Y. The karyotype was confirmed as 45,X[29]/46,X,idic(Y)(q10)[31]. ish idic(Y)(q10)(RP11-115H13x2) (SRY+) by FISH. While in patient 2, the sSMC was originated from chromosome X, whose karyotype was determined as 45, X[71]/46,X, r(X)(p11.23q21)[29]. ish r(X) (p11.23q21)(AL591394.11xAC092268.3).</p><p><b>CONCLUSION</b>Using cytogenetic and molecular cytogenetic analyses, we have identified the sSMCs in two patients with Turner syndrome, which was helpful to the clinical diagnosis and treatment.</p>

Mutation screening of the dystrophin gene in 14 Chinese Duchenne/Becker muscular dystrophy patients without gross deletions / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To search for the dystrophin gene mutations of Duchenne muscular dystrophy (DMD) patients without gross deletions, in order to offer accurate genetic counseling and prenatal diagnosis for those families.</p><p><b>METHODS</b>All 79 exons of the dystrophin gene as well as its 5'-UTR and 3'-UTR of 14 Chinese DMD/Becker muscular dystrphy (BMD) patients without detectable gross deletions were screened by denaturing high performance liquid chromatography (DHPLC) and heteroduplex fragments were identified by subsequent sequencing.</p><p><b>RESULTS</b>Seven causative point mutations, including two novel ones, were detected in 7 patients. Fourteen known polymorphisms and 7 unknown intronic variations were also detected. Five mothers of the patients were obligate carriers.</p><p><b>CONCLUSION</b>DHPLC is an efficient way of identifying point mutations and the female carriers in DMD families.</p>