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1.
Article in Chinese | WPRIM | ID: wpr-879600

ABSTRACT

OBJECTIVE@#To screen for mutations of fragile X mental retardation 1 (FMR1) gene during early and middle pregnancy and provide prenatal diagnosis for those carrying high-risk CGG trinucleotide expansions.@*METHODS@#Peripheral blood samples of 2316 pregnant women at 12 to 21(+6) gestational weeks were collected for the extraction of genomic DNA. CGG repeats of the FMR1 gene were detected by fluorescence PCR and capillary electrophoresis. Genetic counseling and prenatal diagnosis were provided for 3 women carrying the premutations.@*RESULTS@#The carrier rate of CGG repeats of the FMR1 gene was 1 in 178 for the intermediate type and 1 in 772 for the premutation types. The highest frequency allele of CGG was 29 repeats, which accounted for 49.29%, followed by 30 repeats (28.56%) and 36 repeats (8.83%). In case 1, the fetus had a karyotype of 45,X, in addition with premutation type of CGG expansion of the FMR1 gene. Following genetic counseling, the couple chose to terminate the pregnancy through induced labor. The numbers of CGG repeats were respectively 70/- and 29/30 for the husband and wife. In case 2, amniocentesis was performed at 20 weeks of gestation. The number of CGG repeats of the FMR1 gene was 29/-. No abnormality was found in the fetal karyotype and chromosomal copy number variations. The couple chose to continue with the pregnancy. Case 3 refused prenatal diagnosis after genetic counseling and gave birth to a girl at full term, who had a birth weight of 2440 g and no obvious abnormality found during follow-up.@*CONCLUSION@#Pregnant women should be screened for FMR1 gene mutations during early and middle pregnancy, and those with high-risk CGG expansions should undergo prenatal diagnosis, genetic counseling and family study.


Subject(s)
DNA Copy Number Variations , Female , Fragile X Mental Retardation Protein/genetics , Fragile X Syndrome/genetics , Genetic Counseling , Humans , Mutation , Pregnancy , Trinucleotide Repeat Expansion , Trinucleotide Repeats
2.
Arq. neuropsiquiatr ; 76(8): 555-562, Aug. 2018. tab, graf
Article in English | LILACS | ID: biblio-950577

ABSTRACT

ABSTRACT Spinocerebellar ataxias (SCA) are a clinically and genetically heterogeneous group of monogenic diseases that share ataxia and autosomal dominant inheritance as the core features. An important proportion of SCAs are caused by CAG trinucleotide repeat expansions in the coding region of different genes. In addition to genetic heterogeneity, clinical features transcend motor symptoms, including cognitive, electrophysiological and imaging aspects. Despite all the progress in the past 25 years, the mechanisms that determine how neuronal death is mediated by these unstable expansions are still unclear. The aim of this article is to review, from an historical point of view, the first CAG-related ataxia to be genetically described: SCA 1.


RESUMO As ataxias espinocerebelares (SCA) são um grupo clínico e geneticamente heterogêneo de doenças monogênicas que compartilham ataxia e herança autossômica dominante como características principais. Uma proporção importante de SCAs é causada por expansões de repetição de trinucleotídeos CAG na região de codificação de diferentes genes. Além da heterogeneidade genética, os aspectos clínicos transcendem os sintomas motores, incluindo aspectos cognitivos, eletrofisiológicos e de imagem. Apesar de todo o progresso feito nos últimos 25 anos, os mecanismos que determinam como se dá a morte neuronal mediada por essas expansões instáveis ainda não estão claros. O objetivo deste artigo é revisar, de um ponto de vista histórico, a primeira ataxia geneticamente relacionada com o CAG descrita: SCA 1.


Subject(s)
Humans , History, 20th Century , Spinocerebellar Ataxias/genetics , Ataxin-1/genetics , Sleep Wake Disorders/physiopathology , Magnetic Resonance Imaging/methods , Trinucleotide Repeat Expansion/genetics , Spinocerebellar Ataxias/history , Spinocerebellar Ataxias/therapy , Spinocerebellar Ataxias/diagnostic imaging , Depression/physiopathology , Neuroimaging/methods , Cognitive Dysfunction/physiopathology , Ataxin-1/history
3.
Article in Chinese | WPRIM | ID: wpr-345399

ABSTRACT

<p><b>OBJECTIVE</b>To study the pattern of CGG repeat instability within germline cells derived from two male fetuses affected with Fragile X syndrome (FXS).</p><p><b>METHODS</b>The length and methylation status of CGG repeats within the testes of a fetus carrying a full FXS mutation and another fetus carrying mosaicism FXS mutation were analyzed with Southern blotting and AmplideX FMR1 PCR. Immunohistochemistry was also applied for the measurement of FMR1 protein (FMRP) expression within the testes.</p><p><b>RESULTS</b>For the fetus carrying the full mutation, Southern blotting analysis of the PCR product has detected an expected band representing the full mutation in its brain and a premutation band of > 160 CGG repeats in its testis. Whereas the pattern of premutation/full mutation in mosaic testis was similar to that in peripheral blood and no sign of contracted fragment was found other than a band of about 160 CGG repeats. Immunohistochemistry assay with a FMRP-specific antibody demonstrated a number of FMRP-positive germ cells, which suggested a contraction from full mutation to premutation alleles.</p><p><b>CONCLUSION</b>This study has clarified the instability pattern of CGG repeat and expression of FMRP protein within the testes of fetuses affected with FXS, confirming that the CGG repeat can contract progressively within the germline. The FMRP expression in the testis is consistent with spermatogonium proliferation, and thus the contraction from full mutation to unmethylated premutations may occur for the requirement of FMRP expression during spermatogenesis. The better understanding of FMRP function during germ cell proliferation may elucidate the mechanism underlying the contraction of full FXS mutation in male germline.</p>


Subject(s)
Abortion, Eugenic , Blotting, Southern , Brain , Embryology , Metabolism , DNA Methylation , Fatal Outcome , Fetus , Cell Biology , Metabolism , Fragile X Mental Retardation Protein , Genetics , Metabolism , Fragile X Syndrome , Diagnosis , Genetics , Humans , Immunohistochemistry , Male , Mosaicism , Mutation , Polymerase Chain Reaction , Spermatozoa , Metabolism , Testis , Cell Biology , Embryology , Metabolism , Trinucleotide Repeat Expansion , Genetics
4.
Article in Chinese | WPRIM | ID: wpr-345398

ABSTRACT

<p><b>OBJECTIVE</b>To explore the clinical and genetic characteristics of patients with dentatorubro-pallidoluysian atrophy (DRPLA).</p><p><b>METHODS</b>DNA analysis for DRPLA gene was performed in two patients. Clinical features and genetic testing of Chinese DRPLA patients reported in the literature were reviewed in terms of initial symptoms, CAG repeat and age of onset.</p><p><b>RESULTS</b>Both families were confirmed by genetic analysis. In family 1, the number of CAG repeat in the proband, his brother and his mother was determined respectively as 8/65, 8/53 and 8/18. In family 2, the number of CAG repeat was respectively 13/63, 13/18, 18/52 and 13/13 in the proband, his brother, his father and his mother. The size of the expanded CAG repeats has inversely correlated with the age at onset (P<0.05, r=- 0.555). The age at onset of epilepsy was 10 and that for the onset of ataxia is forty years in initial symptom.</p><p><b>CONCLUSION</b>The clinical characteristics of DRPLA include epilepsy, ataxia and cognitive impairment. The initial symptoms are epilepsy in adolescence and ataxia in adults. The size of expanded CAG repeats inversely correlates with the age at onset. The initial symptoms are different with different age of onset. It is difficult to diagnose DRPLA at an early stage.</p>


Subject(s)
Adolescent , Adult , Aged , Atrophy , Genetics , Basal Ganglia Diseases , Diagnosis , Genetics , DNA Mutational Analysis , Dentate Gyrus , Pathology , Family Health , Female , Globus Pallidus , Pathology , Humans , Male , Middle Aged , Nerve Tissue Proteins , Genetics , Pedigree , Trinucleotide Repeat Expansion , Genetics , Young Adult
5.
Article in English | WPRIM | ID: wpr-164787

ABSTRACT

PURPOSE: We examined the prevalence and CGG/AGG repeat structure of expanded alleles of the FMR1 gene in preconceptional and pregnant Korean women. MATERIALS AND METHODS: The CGG repeats in the FMR1 genes of 1,408 women were analyzed by polymerase chain reaction and Southern blot analysis. To estimate the prevalence of expansion alleles, the individuals were divided into low risk and high risk group. RESULTS: Within this population, 98.4% had normal alleles and 1.6% had abnormal alleles including intermediate (0.6%), premutation (0.5%), full mutation (0.1%), and hemizygous (0.4%) alleles. There were 2 premutation alleles (1:666, 95% confidence interval [CI] 1:250-1,776) in the low risk group and 5 premutation alleles (1:15, 95% 1:6-36) in the high risk group. There were 8 intermediate alleles (1:167, 95% CI 1:130-213) in the low risk group and 1 intermediate alleles (1:76, 95% CI 1:11-533) in the high group. Six of the 7 premutation alleles did not contain AGG interruptions within the repeats and 1 had a single AGG interruption. Four of the 9 intermediate alleles contained 2-3 AGG, 4 had a single AGG, and 1 had no AGG interruptions. CONCLUSION: Our study demonstrates the prevalence and CGG/AGG structure of expansion alleles in Korean women. The identified premutation prevalence is higher than that of other Asian populations and lower than that of Caucasian populations. Although our study is limited by size and population bias, our findings could prove useful for genetic counseling of preconceptional or pregnant women.


Subject(s)
Alleles , Asians , Bias , Blotting, Southern , Carrier State , Female , Fragile X Syndrome , Gene Frequency , Genetic Counseling , Humans , Mass Screening , Polymerase Chain Reaction , Pregnant Women , Prevalence , Trinucleotide Repeat Expansion
6.
Article in English | IMSEAR | ID: sea-158448

ABSTRACT

Background & objectives: spinocerebellar ataxia 7 (SCA7) is a rare form of neurodegenerative disorder with the clinical manifestation of cerebellar ataxia and retinal degeneration. In this study we describe the clinico-genetic characteristics of nine SCA7 families of Indian origin and cross compare these with other available worldwide studies. Methods: Thirty five individuals from nine SCA7 families were clinico-genetically characterized and CAG repeat distribution analysis was carried out in 382 control DNA samples from healthy controls (derived from 21 diverse Indian populations based on ethnic and linguistic and geographical location). Results: Of the nine families studied, 22 affected individuals and one asymptomatic carrier were identified. The average age at disease onset was 23.4±12.6 yr. The length of expanded CAG ranged from 40-94 with mean value of 53.2±13.9. The main clinical findings in affecteds individuals included cerebellar ataxia, and retinal degeneration along with hyper-reflexia (95%), slow saccades (85%) and spasticity (45%). Analysis of the association of number of CAG repeats with disease onset revealed that <49 repeats were associated with earlier age at onset in South East Asians compared to European populations. Further analysis of CAG repeats from 21 diverse Indian populations showed pre-mutable repeats (28-34) alleles in the IE-N-LP2 population. Six of the nine families identified in this study belonged to the same ethnic population. Interpretations & conclusion: Our results show that presenece of SCA7 is relatively rare and confined to one ethnic group from Haryana region of India. We observed a homogeneous phenotypic expression of SCA7 mutation as described earlier and an earlier age of onset in our patients with CAG <49. The identification of pre-mutable allele in IE-N-LP2 suggests this population to be at the risk of SCA7.


Subject(s)
Adult , Aged , Humans , Genetic Association Studies , Genotype , India , Middle Aged , Mutation , Population , Spinocerebellar Ataxias/ethnology , Spinocerebellar Ataxias/genetics , Trinucleotide Repeat Expansion/genetics
7.
Chinese Medical Journal ; (24): 1714-1723, 2015.
Article in English | WPRIM | ID: wpr-231704

ABSTRACT

<p><b>BACKGROUND</b>Spinocerebellar ataxias (SCAs) are a group of neurodegenerative disorders that primarily cause the degeneration in the cerebellum, spinal cord, and brainstem. We study the clinical characteristics, radiological features and gene mutation in Chinese families with SCAs.</p><p><b>METHODS</b>In this study, we investigated 10 SCAs Chinese families with SCA1, SCA3/Machado-Joseph disease (MJD), SCA7, SCA8. There were 27 people who were genetically diagnosed as SCA, of which 21 people showed clinical symptoms, and 6 people had no clinical phenotype that we called them presymptomatic patients. In addition, 3 people with cerebellar ataxia and cataracts were diagnosed according to the Harding diagnostic criteria but failed to be recognized as SCAs on genetic testing. Clinical characteristic analyses of each type of SCAs and radiological examinations were performed.</p><p><b>RESULTS</b>We found that SCA3/MJD was the most common subtype in Han population in China, and the ratio of the pontine tegmentum and the posterior fossa area was negatively correlated with the number of cytosine-adenine-guanine (CAG) repeats; the disease duration was positively correlated with the International Cooperative Ataxia Rating Scale score; and the CAG repeats number of abnormal alleles was negatively correlated with the age of onset.</p><p><b>CONCLUSIONS</b>Collectively our study is a systematic research on SCAs in China, which may help for the clinical diagnosis and prenatal screening of this disease, and it may also aid toward better understanding of this disease.</p>


Subject(s)
Adult , DNA Repeat Expansion , Genetics , Female , Humans , Machado-Joseph Disease , Genetics , Pathology , Male , Mutation , Genetics , Spinocerebellar Ataxias , Genetics , Pathology , Trinucleotide Repeat Expansion , Genetics
8.
Article in Chinese | WPRIM | ID: wpr-287991

ABSTRACT

<p><b>OBJECTIVE</b>To analyze the clinical and genetic features of a family with Parkinson's disease caused by expansion of CAG triplet repeat in the ATXN2 gene.</p><p><b>METHODS</b>The CAG/CAA repeat in the ATXN2 gene was analyzed by polymerase chain reaction (PCR) and Sanger sequencing.</p><p><b>RESULTS</b>Molecular testing has documented a pathological heterozygous expansion of the CAG repeat from 33 to 35 in 6 patients and other 8 family members. Two patients had pure CAG triplet repeat expansion in their ATXN2 gene, while others had CAA interruption.</p><p><b>CONCLUSION</b>Expanded CAG/CAA repeat in the ATXN2 gene is the causative mutation of the disease in this family.The 8 members with expanded CAG/CAA repeat may be asymptomatic patients. It is supposed that the number and configuration of the ATXN2 CAG/CAA repeat expansion may play an important role in the phenotypic variability of Parkinson's disease.</p>


Subject(s)
Aged , Ataxin-2 , Genetics , Base Sequence , Family Health , Female , Genetic Predisposition to Disease , Genetics , Humans , Male , Middle Aged , Parkinson Disease , Genetics , Pathology , Pedigree , Polymerase Chain Reaction , Sequence Analysis, DNA , Methods , Trinucleotide Repeat Expansion , Genetics
9.
IBJ-Iranian Biomedical Journal. 2014; 18 (1): 28-33
in English | IMEMR | ID: emr-130681

ABSTRACT

Friedreich ataxia [FRDA] is an autosomal recessive disorder caused by guanine-adenine-adenine [GAA] triplet expansions in the FXN gene. Its product, frataxin, which severely reduces in FRDA patients, leads to oxidative damage in mitochondria. The purpose of this study was to evaluate the triple nucleotide repeated expansions in Iranian FRDA patients and to elucidate distinguishable FRDA clinical differences in these patients. A number of 22 Iranian patients [8 females and 14 males] from 16 unrelated families were studied. DNA was extracted from the peripheral blood of patients. The frequency and length of [GAA]n repeats in intron 1 of the FXN gene were analyzed using long-range PCR. In this study, the clinical criteria of FRDA in our patients and the variability in their clinical signs were also demonstrated. An inverse relationship was observed between GAA repeat size and the age of onset. Although some distinguishable clinical features [such as limb ataxia and lower limb areflexia] were found in our patients, 90-95% of them had extensor plantar response and dysarthria. The results showed only one positive diabetes patient and also different effects on eye movement abnormality among our patients. The onset age of symptoms showed a significant inverse correlation with allele size in our patients [P>0.05]. Based on comparisons of the clinical data of all patients, clinical presentation of FRDA in Iranian patients did not differ significantly from other FRDA patients previously reported


Subject(s)
Humans , Male , Female , Trinucleotide Repeat Expansion , Mitochondria , Iron-Binding Proteins
10.
Article in Chinese | WPRIM | ID: wpr-254512

ABSTRACT

Hereditary spinocerebellar ataxia type 17 (SCA17) is an autosomal dominantly inherited progressive degenerative disease of the nervous system. Also known as Huntington's disease-like 4(HDL4), SCA17 mainly features ataxia, muscle dystonia and psychiatric symptoms. The gene predisposing to SCA17 has been mapped and cloned, which encodes a TATA-binding protein (TBP). A CAG repeat expansion in the coding region of TBP gene can cause polyglutamine chain extension in the protein. This paper reviews recent progress in the research on SCA17 in regard to its clinical, etiology, pathology and pathogenesis.


Subject(s)
Animals , Humans , Huntington Disease , Genetics , Pathology , Spinocerebellar Ataxias , Genetics , Pathology , TATA-Box Binding Protein , Genetics , Trinucleotide Repeat Expansion
11.
Article in Chinese | WPRIM | ID: wpr-291689

ABSTRACT

<p><b>OBJECTIVE</b>To report on a Chinese family from Wenzhou with genetically confirmed Kennedy disease and describe its clinical and genetic features.</p><p><b>METHODS</b>The clinical phenotype and the level of relevant biochemical markers were assessed. To determine the number of CAG repeats in the exon 1 of androgen receptor (AR) gene, genomic DNA was extracted from peripheral blood samples of the family members, amplified by PCR and identified by DNA sequencing.</p><p><b>RESULTS</b>The proband showed predominantly proximal limb weakness, fasciculation, muscle atrophy, gynecomastia, sexual dysfunction and increased serum creatine kinase. Myopathy and neuropathy were identified by electromyography. Two other affected males and 2 affected female carriers were identified to carry an expanded CAG repeat in the AR gene. The numbers of CAG repeats were found to be 43 in the proband, 43 and 42 in the other two affected males, one of which had similar clinical symptoms to the proband.</p><p><b>CONCLUSION</b>The family was diagnosed with Kennedy disease by analysis of the AR gene.</p>


Subject(s)
Adolescent , Adult , Base Sequence , Bulbo-Spinal Atrophy, X-Linked , Blood , Diagnosis , Genetics , Creatine Kinase , Blood , Female , Humans , Male , Middle Aged , Molecular Sequence Data , Pedigree , Receptors, Androgen , Genetics , Trinucleotide Repeat Expansion , Young Adult
12.
Article in Chinese | WPRIM | ID: wpr-291688

ABSTRACT

<p><b>OBJECTIVE</b>To screen for potential mutations of androgen receptor (AR) gene in a patient clinically diagnosed as Kennedy disease.</p><p><b>METHODS</b>Polyglutamine expansion (PQE) induced by a duplication of CAG trinucleotide tandem-repeat in exon 1 of the AR gene was detected with PCR and T-clone sequencing.</p><p><b>RESULTS</b>Compared with the number of CAG repeat of 22 in the normal allele, the number of CAG repeats has increased to 45 in the mutant allele carried by the patient. This has fit with the diagnostic criteria for Kennedy disease.</p><p><b>CONCLUSION</b>A mutation of PQE has been detected in the patient with Kennedy disease. Detection of PQE in AR gene can be used as reliable method to identify the Kennedy disease.</p>


Subject(s)
Base Sequence , Bulbo-Spinal Atrophy, X-Linked , Blood , Diagnosis , Genetics , Creatine Kinase , Blood , Humans , Male , Middle Aged , Molecular Sequence Data , Receptors, Androgen , Genetics , Trinucleotide Repeat Expansion
13.
Indian J Hum Genet ; 2013 July-Sept ;19 (3): 320-324
Article in English | IMSEAR | ID: sea-156584

ABSTRACT

Mitochondria contains a single deoxyribonucleic acid (DNA) polymerase, polymerase gamma (POLG) mapped to long arm of chromosome 15 (15q25), responsible for replication and repair of mitochondrial DNA. Exon 1 of the human POLG contains CAG trinucleotide repeat, which codes for polyglutamate. Ten copies of CAG repeat were found to be uniformly high (0.88) in different ethnic groups and considered as the common allele, whereas the mutant alleles (not -10/not -10 CAG repeats) were found to be associated with oligospermia/oligoasthenospermia in male infertility. Recent data suggested the implication of POLG CAG repeat expansion in infertility, but are debated. The aim of our study was to explore whether the not -10/not -10 variant is associated with spermatogenic failure. As few study on Indian population have been conducted so far to support this view, we investigated the distribution of the POLG CAG repeats in 61 infertile men and 60 normozoospermic control Indian men of Tamil Nadu, from the same ethnic background. This analysis interestingly revealed that the homozygous wild type genotype (10/- 10) was common in infertile men (77% - 47/61) and in normozoospermic control men (71.7% - 43/60). Our study failed to confirm any influence of the POLG gene polymorphism on the efficiency of the spermatogenesis.


Subject(s)
DNA-Directed DNA Polymerase/genetics , Humans , India/epidemiology , Infertility, Male/genetics , Male , Polymorphism, Genetic/genetics , Spermatozoa/abnormalities , Trinucleotide Repeat Expansion/genetics
14.
Rio de Janeiro; s.n; 2013. 89 p. ilus, tab.
Thesis in Portuguese | LILACS | ID: lil-711961

ABSTRACT

O retardo mental (RM) representa um problema de saúde pública mundial ainda negligenciado no Brasil e, em especial nas regiões mais pobres como o Nordeste. A síndrome do X frágil (SXF) é uma das formas mais estudadas de RM hereditário em seres humanos. Esta doença monogênica, de herança ligada ao X dominante, é decorrente de uma mutação no exon 1 do gene FMR1, localizado na região Xq27.3. A mutação no FMR1 se caracteriza pelo aumento de repetições de trinucleotídios CGG em tandem na região 5’ UTR desse gene, sendo a expansão dessas trincas o principal evento mutacional responsável pela SXF. De maneira geral, os fenótipos cognitivos de indivíduos do sexo masculino com a síndrome incluem deficiência intelectual de moderada à grave. No presente trabalho, realizamos um estudo transversal da SXF em indivíduos portadores de retardo mental de causa desconhecida, engajados em Programas de Educação Especial e em instituições psiquiátricas de São Luís-MA, rastreando amplificações de sequências trinucleotídicas no gene FMR1. A amostra foi composta por 238 indivíduos do sexo masculino, não aparentados, na faixa etária de 4 a 60 anos (média = 21 ± 9 anos). O DNA dos participantes foi obtido a partir de 5 mL de sangue coletados em tubos com anti-coagulante EDTA e a análise molecular da região gênica de interesse foi realizada através da reação em cadeia da polimerase, utilizando-se três primers. Dentre os indivíduos triados quanto à presença de mutações no gene FMR1, apenas um apresentou um resultado inconclusivo e 2 (0,84%) foram positivos para a SXF, sendo que um deles (3503) apresentou mais de 200 repetições CGG no locus FRAXA e o outro indivíduo (3660) apresentou uma deleção de ~197 pb envolvendo parte das repetições CGG e uma região proximal às repetições CGG. Ambos possuíam história familiar de RM ligado ao X. No indivíduo 3503 observamos as seguintes características clínicas: temperamento dócil, orelhas grandes, mandíbula proeminente e flacidez ligamentar ...


Mental retardation (MR) is considered a global public health problem in Brazil and it is still ignored mainly in poor regions like Northeast Brazil. The fragile X syndrome (FXS) is one of the most common heritable disease in humans. it is a monogenic disease with X-linked dominant inheritance due to a mutation in exon 1 of the FMR1 gene, located at Xq27.3 region. The mutation in FMR1 is characterized by the increase in number of CGG repeats in the 5 'UTR of the gene. This expansion of CGG triplets in the first exon of the FMR1 gene is the main mutational event responsible for FXS. In general, the cognitive phenotypes of males with this syndrome include intellectual disabilities from moderate to severe. In this work, we conducted a cross-sectional study of FXS in individuals with MR of unknown cause, in Especial Education Programs and Psyquiatric Instituitions in São Luís-MA, by screening for amplifications of trinucleotide sequences within the FMR1 gene. The sample consisted of 238 unrelated males, which ages were from 4 to 60 years (mean = 21 ± 9 years). The DNA of all individuals was obtained from 5 mL of peripheral blood which was colected in EDTA-anticoagulated tubes. The molecular analysis of the genetic region of interest was performed by polimerase chain reaction using three primers. Of the individuals screened for the presence of the mutation in the FMR1 gene, only one was inconclusive and two (0.84%) were positive for FXS. One (3503) presented more than 200 CGG repeats in FRAXA locus, and the other (3660) presented with a ~ 197 bp deletion involving part of CGG repeats and a proximal region to the CGG repeats. Both of these individuals have family history of X-linked Mental Retardation. The individual 3503 has the following clinical features: docile temperament, large ears, prominent jaw and ligamentous laxity. The individual 3660 presents hyperactivity, poor contact with eyes, large ears, prominent jaw, pectus excavatum, macroorchidism and little ...


Subject(s)
Humans , Male , Intellectual Disability/diagnosis , Intellectual Disability/genetics , Fragile X Syndrome/diagnosis , Fragile X Syndrome/genetics , Diagnosis, Differential , Exons/genetics , Mutation/genetics , Fragile X Mental Retardation Protein/genetics , Polymerase Chain Reaction/methods , Sequence Analysis, DNA , Trinucleotide Repeat Expansion
15.
Article in Chinese | WPRIM | ID: wpr-237248

ABSTRACT

<p><b>OBJECTIVE</b>To compare the distribution of (CAG)n and (GGN)n repeats polymorphisms of androgen receptor (AR) gene between Hui and Han ethnic Chinese from Ningxia.</p><p><b>METHODS</b>Genotypes of above repeats were determined with DNA sequencing method.</p><p><b>RESULTS</b>The distribution of (GGN)n repeats was significantly different between the two ethnic groups (P< 0.01), though no such difference was detected with (CAG)n repeats (P> 0.05). Particularly, Han Chinese women carrying 23 GGN repeats were significantly fewer (48.4%) than Hui women (64.7%, P=0.01).</p><p><b>CONCLUSION</b>The distribution of GGN repeat is significantly differently among Hui and Han Chinese ethnics from Ningxia.</p>


Subject(s)
Alleles , Asians , Genetics , Base Sequence , China , Ethnology , Female , Genotype , Humans , Male , Molecular Sequence Data , Polymorphism, Genetic , Population Groups , Genetics , Receptors, Androgen , Genetics , Trinucleotide Repeat Expansion , Trinucleotide Repeats
17.
Arq. neuropsiquiatr ; 69(3): 419-423, June 2011. tab
Article in English | LILACS | ID: lil-592495

ABSTRACT

Huntington's disease (HD) is a neurodegenerative disorder characterized by chorea, behavioral disturbances and dementia, caused by a pathological expansion of the CAG trinucleotide in the HTT gene. Several patients have been recognized with the typical HD phenotype without the expected mutation. The objective of this study was to assess the occurrence of diseases such as Huntington's disease-like 2 (HDL2), spinocerebellar ataxia (SCA) 1, SCA2, SCA3, SCA7, dentatorubral-pallidoluysian atrophy (DRPLA) and chorea-acanthocytosis (ChAc) among 29 Brazilian patients with a HD-like phenotype. In the group analyzed, we found 3 patients with HDL2 and 2 patients with ChAc. The diagnosis was not reached in 79.3 percent of the patients. HDL2 was the main cause of the HD-like phenotype in the group analyzed, and is attributable to the African ancestry of this population. However, the etiology of the disease remains undetermined in the majority of the HD negative patients with HD-like phenotype.


A doença de Huntington (DH) é uma doença neurodegenerativa caracterizada por coréia, alterações comportamentais e demência, causada por uma expansão patológica do trinucleotídeo CAG no gene HTT. Vários pacientes têm sido descritos com o fenótipo típico para a DH porém sem a mutação esperada. O objetivo deste estudo foi avaliar a ocorrência de doenças como doença de Huntington-símile 2 (DHS-2), ataxias espinocerebelares tipo 1, 2, 3 e 17, atrofia dentatorubral-palidoluisiana e coreo-acantocitose (CAc) entre 29 pacientes brasileiros com fenótipo doença de Huntington-símile. No grupo analisado, encontramos 3 pacientes com DHS-2 e 2 pacientes com CAc. O diagnóstico permaneceu obscuro em 79,3 por cento dos pacientes. DHS-2 foi a principal causa do fenótipo DH-símile no grupo analisado, provavelmente devido a ancestralidade africana na população brasileira. Entretanto, a etiologia permaneceu indeterminada na maioria dos pacientes avaliados.


Subject(s)
Adult , Female , Humans , Male , Huntington Disease/diagnosis , Myoclonic Epilepsies, Progressive/diagnosis , Neuroacanthocytosis/diagnosis , Spinocerebellar Ataxias/diagnosis , Trinucleotide Repeat Expansion/genetics , Cross-Sectional Studies , Huntington Disease/genetics , Myoclonic Epilepsies, Progressive/genetics , Neuroacanthocytosis/genetics , Phenotype , Spinocerebellar Ataxias/genetics
18.
Article in Chinese | WPRIM | ID: wpr-326977

ABSTRACT

<p><b>OBJECTIVE</b>To investigate the CAG trinucleotide repeat expansion and clinical characteristics of a Chinese Uygur family with spinocerebellar ataxia type 12 (SCA12) in Xinjiang Uygur Autonomous Region.</p><p><b>METHODS</b>In the Uygur SCA12 family, 6 patients and 54 "healthy" members were analyzed by polymerase chain reaction, agarose gel electrophoresis, recombinant DNA technology by T-Vector cloning and restriction enzyme digestion, and direct sequencing. The diagnosis of SCA12 was confirmed. The CAG trinucleotide expansion was also analyzed.</p><p><b>RESULTS</b>Six members in the family were diagnosed as SCA12 patients and 13 were presymptomatic. Five of them were successfully detected by sequencing. The CAG repeat numbers of 4 patients were 47, 51, 52 and 53, respectively, and 48 in the presymptomatic patient. We also observed that in the CAG repeat region there was replacement of single nucleotide C, A or G.</p><p><b>CONCLUSION</b>Forty-seven CAG repeats of SCA12 has been reported as the shortest known causative expanded alleles. The present study is the first report of the characteristics of SCA12 gene mutation in Chinese. It will provide basis for the accurate classification, disease etiology, treatment and prenatal diagnosis of this disease.</p>


Subject(s)
Adult , Base Sequence , Case-Control Studies , China , Female , Humans , Male , Molecular Sequence Data , Mutation , Pedigree , Polymerase Chain Reaction , Sequence Analysis, DNA , Spinocerebellar Ataxias , Diagnosis , Genetics , Trinucleotide Repeat Expansion
19.
Article in Chinese | WPRIM | ID: wpr-234395

ABSTRACT

Polyglutamine (Poly Q) diseases are a group of neurodegenerative disorders, caused by the formation of PolyQ mutants due to trinucleotide repeats expansion in coding regions of disease-causing genes, which eventually lead to selective neuronal degeneration and death with unclarified pathogenesis. As a new type of genetic regulatory factor, microRNA (miRNA) plays an important role in modulating gene expression in eukaryote. During the recent years, more attention was paid to roles and related mechanism of miRNA involving in neurodegenerative disease, especially PolyQ diseases. This review is focused on research progress in roles of miRNA in the pathogenesis of PolyQ diseases.


Subject(s)
Eukaryota , MicroRNAs , Genetics , Physiology , Nerve Degeneration , Neurodegenerative Diseases , Genetics , Peptides , Genetics , Trinucleotide Repeat Expansion , Genetics , Trinucleotide Repeats , Genetics
20.
Article in Chinese | WPRIM | ID: wpr-234373

ABSTRACT

<p><b>OBJECTIVE</b>To assist the establishment of platform and provide the reference standard for mutation detection in spinocerebellar ataxia (SCA) subtypes 1, 2, 3, 6, 7, 8, 10, 12, 17 and dentatorubral-pallidoluysian atrophy (DRPLA) in Chinese Han population.</p><p><b>METHODS</b>The nucleotide repeat numbers of the 9 SCA subtypes and DRPLA were detected using fluorescence-PCR and capillary gel electrophoresis technique in 300 healthy Chinese Han individuals.</p><p><b>RESULTS</b>Among the 300 healthy controls, the range of the CAG trinucleotide repeat number was 17 to 35 in SCA1, 14-28 in SCA2, 13-41 in SCA3/MJD, 4-16 in SCA6, 5-17 in SCA7, 5-21 in SCA12, 23-41 in SCA17, and 12-33 in DRPLA; and the range of CTA/CTG trinucleotide repeat number on SCA8 locus was 12-43 and the range of ATTCT pentanucleotide repeat number on SCA10 locus was 9-32. Of which, the 12 CTA/CTG repeats of SCA8, 9 ATTCT repeats of SCA10, 23 CAG repeats of SCA17 were the shortest normal repeat number, while the 41 CAG repeats of SCA3/MJD, 32 CAG repeats of SCA10 were the largest normal number that have not been reported.</p><p><b>CONCLUSION</b>The normal ranges of polynucleotide repeats of different subtypes of SCA vary with geographical areas and ethnicities. It might be associated with the genetic and ethnic backgrounds. This is the first normal reference standard of polynucleotide repeat number of these ten SCA subtypes in Chinese Han.</p>


Subject(s)
Adult , Asians , Ethnology , Genetics , Base Sequence , Case-Control Studies , Humans , Male , Middle Aged , Molecular Sequence Data , Myoclonic Epilepsies, Progressive , Ethnology , Genetics , Spinocerebellar Ataxias , Ethnology , Genetics , Trinucleotide Repeat Expansion
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