Twins from different fathers: A heteropaternal superfecundation case report in Colombia / Gemelos de diferentes padres: un caso de superfecundación heteropaternal en Colombia

Abstract: Heteropaternal superfecundation is an extremely rare phenomenon that occurs when a second ova released during the same menstrual cycle is additionally fertilized by the sperm cells of a different man in separate sexual intercourse. In August, 2018, the Grupo de Genética de Poblaciones e Identificación at Universidad Nacional de Colombia received a request to establish the paternity of a pair of male twins with genetic markers. The following analyses were performed: amelogenin gene, autosomal short tandem repeat (STR), and Y-STR analyses by means of human identification commercial kits, paternity index, and the probability of paternity calculation and interpretation. A paternity index of 2.5134E+7 and a probability of paternity of 99.9999% for twin 2 were obtained while 14 out of 17 Y-chromosome markers and 14 out of 21 autosomal short tandem repeats were excluded for twin 1. The results indicated that the twins have different biological fathers. Although heteropaternal superfecundation is rarely observed among humans given its low frequency, in paternity disputes for dizygotic twins it is mandatory to demand the presence of the two twins in the testing to avoid wrong conclusions.

Resumen: La superfecundación heteropaternal es un fenómeno extremadamente raro que se produce cuando un segundo óvulo, liberado durante el mismo ciclo menstrual, es fertilizado por un espermatozoide de un hombre diferente en relaciones sexuales separadas. En agosto de 2018, el Grupo de Genética de Poblaciones e Identificación de la Universidad Nacional de Colombia recibió una solicitud para establecer la paternidad mediante marcadores genéticos de un par de mellizos varones, en quienes se hizo el análisis del gen de amelogenina, el análisis de repeticiones cortas en tándem (Short Tandem Repeats, STR) autosómicas y del cromosoma Y (Y-STR) mediante kits comerciales de identificación humana y cálculos e interpretación del índice de paternidad y probabilidad de paternidad. Se obtuvo un índice de paternidad de 2,5134E+7 y una probabilidad de paternidad de 99,9999 % para el gemelo 2, en tanto que en el gemelo 1 se excluyeron 14 de los 17 marcadores del cromosoma Y y 14 de los 21 sistemas STR autosómicos evaluados. Los resultados indicaron que los gemelos tienen diferentes padres biológicos. A pesar de que la superfecundación heteropaternal rara vez se observa en humanos debido a su baja frecuencia, en las disputas de paternidad para los gemelos dicigóticos, es obligatorio exigir en la prueba la presencia de los dos gemelos para evitar conclusiones incorrectas.

Assessment of multiple quantitative fluorescence PCR technique for common chromosome ;aneuploidies / 中华检验医学杂志

Objective To evaluate the effectiveness of multiple quantitative fluorescence PCR ( QF-PCR) as a rapid technique for prenatal diagnosis of common chromosome aneuploidies , in order to optimize the prenatal diagnosis and shorten the period of diagnosis.Methods Totally 731 amniotic fluid samples of pregnant subjects ,who were referred to the Women′s Hospital School of Medicine Zhejiang University during August 2013 and September 2015, were analyzed with conventional karyotype and the QF-PCR technique by short tandem repeat(STR) markers to detect chromosomes 13,18,21,X and Y aneuploidies.There were 558 samples detected by single blind method , 173 samples detected by double blind method.Results All of the 731 amniotic fluid samples were tested in this study by QF-PCR and the results were compared to the conventional cytogenetic analysis results of the same sample.Totally 558 samples with single blind method detected 5 trisomy 21, 2 trisomy 18, 1 trisomy 13, 1(45,X), 1(47,XXY), 1(47,XYY), 1(47,XXX) and 1(69,XXX), 173 samples with double blind method detected 1 trisomy 21 and 1 trisomy 18.The rapid QF-PCR assay was successful to detect all aneuploidies involving chromosomes 21, 18, 13, X and Y in prenatal diagnosis , which were verified by chromosome karyotype analysis.The results of QF-PCR method were compared with the results of chromosome karyotype analysis , the positive rate was 15/16, the negative rate was 100%(715/715).Non chimeric chromosome abnormality detection rate was 15/15.Conclusions The multiple QF-PCR was a reliable method of detecting common chromosome aneuploidies for rapid prenatal diagnosis.As an important supplement of karyotype analysis , it was of great significance to optimize and improve the prenatal diagnosis system , and might provide more appropriate diagnostic methods for pregnant women.

Mixture Patterned Short Tandem Repeat Profile in a Perimortem Transfused Patient / 대한법의학회지

Recently, it has been reported that transfused patients can generate admixture-like genetic profiles. As genetic material of the donor can survive for a reasonable time after transfusion, the recipient's genomic DNA is likely to have a mixture pattern. An autopsy case of a man transfused perimortem generated a mixture patterned short tandem repeat profile. Notably, the patient was transfused mostly with nuclear-deficient cells, limiting the donor genetic material available for the recipient. As a result, mixture-like patterns were observed consistently, regardless of change in input DNA content; the sample DNA content, which was serially diluted, ranged from 1 ng to 0.0625 ng. The distributions of foreign peaks appeared to be irreproducible, showing stochastic behaviors throughout the genotyped results. This study suggests that a cautious approach is required when genotyping of a patient who has undergone recent transfusion. One must consider the possibility of obtaining a mixture patterned profile in such patients, and therefore, choose parenchymal organs or tissues for reliable results.

Looking Back at Our 5-Year Experience of Paternity Testing: A Summary / 대한법의학회지

We have been testing familial relationships based on short tandem repeats (STRs) in families who requested it either voluntarily or by order of the court. Here, we present a summary of our 5-year experience of autosomal STR-based paternity tests. A total of 1,431 individuals from 588 cases were tested, including 878 pairs of either of the parent, and a child. Among these 588 cases, genetic information about the other parent was available only for 135 cases. Five hundred eighteen pairs were concluded to be parent-child relations, for which the median paternity index (PI) was 72,826, and the median decimal logarithm was 4.860. Autosomal mutation was observed in nine pairs (1.74%), and the pairs harbored only one mismatched locus among the 15 standard loci (D8S1179, D21S11, D7S820, CSF1PO, D3S1358, TH01, D13S317, D16S539, D2S1338, D19S433, vWA, TPOX, D18S51, D5S818, and FGA). The number of mismatched loci did not increase even after additional loci were included in the study. The observed mutation rates were D13S317 (0.193%), D18S51 (0.193%), D19S433 (0.193%), FGA (0.193%), vWA (0.386%), Penta D (0.387%), and Penta E (0.193%). There were 14 pairs with two mismatched loci, which we excluded through additional tests on either autosomal or X chromosomal STRs, and mitochondrial sequencing. Although PI is useful for determining parent-child relation, it provides indirect information; it is an interpretation of the test results that is based on probability. Additional genotyping on sex chromosome and mitochondrial DNA, or participation of other family members might be beneficial for a reliable conclusion.

Vitamin D Receptor Poly(A) Microsatellite Polymorphism and 25-Hydroxyvitamin D Serum Levels: Association with Susceptibility to Breast Cancer / 한국유방암학회지

PURPOSE: According to previous studies, vitamin D exhibits protective effects against breast cancer via the vitamin D receptor (VDR). There is growing evidence that breast cancer incidence is associated with various polymorphisms of the VDR gene. This study investigates the association of VDR poly(A) microsatellite variants with 25-hydroxyvitamin D (25(OH)D) serum levels and breast cancer risk. METHODS: Polymorphism analysis was performed on a total of 261 blood samples, which were collected from 134 women with breast cancer and 127 controls. Single strand conformation polymorphism was assessed by polymerase chain reaction in combination with sequencing to detect poly(A) lengths for each sample. The vitamin D levels of samples were determined by electrochemiluminescence. RESULTS: The poly(A) variant L allele frequency was significantly higher in cancer patients than in controls (odds ratio [OR], 1.73; 95% confidence interval [CI], 1.16-2.57; p=0.006). Thus, carriers of the L allele (LS and LL genotypes) have a higher risk for breast cancer (OR, 1.86; 95% CI, 1.13-3.05; p=0.013). A larger increase in the risk for breast cancer was found in individuals with the L carrier genotype and lowered 25(OH)D levels. CONCLUSION: The results primarily suggest that VDR gene polymorphism in the poly(A) microsatellite is associated with 25(OH)D levels and that it can affect the breast cancer risk in the female population from northern Iran.

Diversity and genetic structure analysis of three Amazonian Amerindian populations from Colombia / Análisis de la diversidad y la estructura genética de tres poblaciones indígenas amazónicas colombianas

Introduction: In the departments of the Vaupés and Guaviare, in southeastern Colombia, in a transitional area between Amazonia and the eastern plains, inhabit indigenous groups belonging to the Tukanoan (East) and Guahiban linguistic families. Although some studies have dealt with the culture and the cosmology description of these groups, little research has been done on the biological diversity and genetic relationships of such groups.Objective: To estimate the diversity, the structure, and the genetic relationships of one Guahiban and two Tukanoan groups of the Colombian Amazonian region.Methods: Samples were collected (n = 106) from unrelated individuals belonging to the Vaupés native indigenous communities. The DNA was extracted and nine autosomal microsatellites were typed. Several measures of diversity, FST, pairwise FST, and population differentiation between groups were calculated. Finally, it was estimated the genetic distances of the groups studied in relation with other Amazonian, Andean and Central American indigenous people.Results: 1. The genetic diversity found stands within the range of other Amazonian populations, whereas compared to the mestizo and afro-descendant Colombian populations, such diversity showed to be lower. 2. The structure and population differentiation tests showed two clusters; one consisting of the Vaupés Tukanoan and Guaviare Tukanoan groups, and a second one formed by the Guayabero. 3. Tukanoan groups are found to be closer related to the Brazilian Amazonian populations than to the Guayabero.Conclusion: The results of this study suggest that the Guayabero group from Guaviare, are genetically differentiated from those Tukanoan groups of the Vaupés and Guaviare

Short tandem repeat analysis for diagnosing complete hydatidiform mole and coexisting fetus: a casereport and literature review / 中华围产医学杂志

Objective To investigate the parental origin for a rare case of complete hydatidiform mole and coexisting fetus and to discuss its diagnosis and differential diagnosis.Methods Tissues from the fetus,mole and placenta were collected and pathology analysis and chromosome analysis were done.The DNA from the fetus,mole and parents' peripheral blood leukocytes was amplified with five short tandem repeat (STR) markers (D4S2460,D18S488,D21S2039,DXS1205 and DYS219) at the same time to confirm the parental source of the hydatidiform.Results (1) Casereport:A 27-year-old woman,gravida 1,para 0,was found high risk for neural tube defects at 20 weeks of gestation.At 24+5 weeks of gestation,ultrasound examination demonstrated a normal fetus,a normal placenta and a huge mass with a multicystic appearance attached to the placenta with an obvious demarcation.The fetus died at 26 weeks of gestation.Serum human chorionic gonadotropin-β(β -hCG) level decreased obviously during the first two weeks after artificial induction,but elevated at the third week,and β-hCG titers fell to normal after 2 courses of chemotherapy.Fetus autopsy showed no structure abnormality.Histopathologic examination of the hydatidiform showed swelling of chorionic villi with hyperplasia of the trophoblast and formation of central cisterns suggesting of a twin pregnancy consisting of a complete hydatidiform mole and coexisting fetus.(2) Genetic analysis:The karyotype analysis of the normal placental villi was 46,XY; the cell cultures of fetal cartilage tissue and hydatidiform were failed.STR analysis showed that the fetus was diploid from biparental source;the mole was androgenetic source.And the mole had locus both from Y and X chromosome of the father,so it was heterozygous.It was suggested that this case was derived from one single oocyte fertilized with three spermatozoas.Conclusions STR analysis could be used to confirm the diagnosis of complete hydatidiform mole and coexisting fetus and to find the pathogenetic rnechanism.

Gene mapping study for constitutive skin color in an isolated Mongolian population

To elucidate the genes responsible for constitutive human skin color, we measured the extent of skin pigmentation in the buttock, representative of lifelong non-sun-exposed skin, and conducted a gene mapping study on skin color in an isolated Mongolian population composed of 344 individuals from 59 families who lived in Dashbalbar, Mongolia. The heritability of constitutive skin color was 0.82, indicating significant genetic association on this trait. Through the linkage analysis using 1,039 short tandem repeat (STR) microsatellite markers, we identified a novel genomic region regulating constitutive skin color on 11q24.2 with an logarithm of odds (LOD) score of 3.39. In addition, we also found other candidate regions on 17q23.2, 6q25.1, and 13q33.2 (LOD > or = 2). Family-based association tests on these regions with suggestive linkage peaks revealed ten and two significant single nucleotide polymorphisms (SNPs) on the linkage regions of chromosome 11 and 17, respectively. We were able to discover four possible candidate genes that would be implicated to regulate human skin color: ETS1, UBASH3B, ASAM, and CLTC.

Markers for Screening Lynch Syndrome Are Reliable and Useful for Identifying the Specimen Mislabeling

BACKGROUND: During specimen processing in surgical pathology laboratories, specimen-related adverse events (SRAEs), such as mislabeling and specimen mixed-up might occur. In these situations, molecular techniques using short tandem repeat (STR) loci are required to identify the personal identity. Microsatellite instability (MSI) test is widely used for screening the hereditary non-polyposis colon cancer (Lynch syndrome) in surgical pathologies using polymorphic STR markers. We tried to evaluate the applicability of the MSI test for SRAEs. METHODS: We obtained 253 MSI test results to analyze the allele frequencies. After calibrating the estimated nucleotide lengths, we calculated the allele frequencies, a random match probability, and a likelihood ratio (LR) of three dinucleotide STR markers (D5S349, D17S250, and D2S123). RESULTS: The distribution of LR was 136.38 to 5,606,213.10. There was no case of LR10,000. Furthermore, the combined probability of identity was 9.23x10(-4) and the combined power of exclusion was 0.99908. CONCLUSIONS: Using the three STR markers that are recommended for MSI test, all the cases were positively identified in 1% range and about one-third cases showed high LR (>10,000). These results showed that MSI tests are useful to screen the personal identity in case of SRAE in pathology laboratories.

Análisis clínic y molecular de una pacientecon pentasomia del cromoooma x. / Clinical and Molecular Analysis of a Patient with X-Chromosome Pentasomy.

Introducción: la Pentasomia del X (49,XXXXX) es una alteración cromosómica poco frecuente, que afecta a mujeres y fue descrita en 1963 por Kesaree y Wooley. Hasta la fecha se han reportado menos de 30 casos en la literatura. Se presenta un caso de pentasomia del cromosoma X, y mediante técnicas de biología molecular (microsatélites) se determino el origen materno de los cromosomas X adicionales. Caso clínico: paciente de 28 meses, con talla baja proporcionada, braquicefalia, fascies característica, genitales externos femeninos con labios mayores hipoplásicos, braquidactilia, clinodactilia bilateral del quinto dedo, luxación de rodilla derecha, deformidad en varo. Se realizó cariotipo en sangre periférica que reportó un complemento cromosómico 49,XXXXX. Materiales y métodos: se realizó extracción de ADN y PCR para la amplificación de ocho microsatélites o STR’s tetra y dinucleotídicos situados a lo largo del cromosoma X. Los productos amplificados se analizaron en el secuenciador ALF EXPRESS. Con la información alélica se realizó la construcción del haplotipo y el análisis de dosis génica mediante la determinación del área bajo la curva. Resultados y discusión: el análisis de los ocho STR’s realizados en la paciente y sus padres, permitió establecer que los cromosomas X extras corresponden a información alélica heredada de la madre. Se analizan los resultados y los eventos que se han documentado como relacionados con los fenómenos de no disyunción. Conclusión: el origen de la doble no disyunción que generó la pentasomia es materna, en donde un ovulo tetrasómico, con cuatro copias de cromosoma X fue fecundado con un espermatozoide monosómico normal.

Introduction: Pentasomy X is a rare chromosomal disorder which affects women. It was first described in 1963 by Kesaree and Wooley. Up to date, less than 30 cases have been reported. We report a case of 28 month old female patient with clinical features of Pentasomy X. Cytogenetic and molecular analysis revealed that her karyotype was 49,XXXXX and that the additional X chromosomes were maternal in origin. Case report: We present a 28 month old female patient with short stature, brachycephaly, characteristic facies, with female external genitalia, hypoplasic labia majora, brachydactyly, bilateral clinodactyly of the fifth finger, dislocation of the right knee with genu varum deformities. Chromosome analysis revealed a karyotype of 49, XXXXX. Materials and methods: We performed DNA extraction and subsequent PCR amplification of 8 microsatellites (STR’s) throughout the X chromosome. The amplified products were analyzed in the ALF EXPRESS sequencer. The allelic information obtained was used to construct haplotypes and to analyze gene dosage through the determination of the area under the curve. Results and discussion: Through the analysis of eight STR’s in the patient and her parents we were able to determine that the extra X chromosomes were inherited from the mother. We analyze our results and other well documented events that have been related to non-disjunctions. Conclusion: We confirmed through molecular analysis of X-linked DNA markers that the aneuploidy developed from two maternal non-disjunctions.

Genetic genesis of choriocarcinoma / 中华妇产科杂志

Objective To distinguish choriocarcinoma from gestational or non-gestational choriocarcinoma and also identify the causative pregnancy of gestational choriocarcinoma by the genetic origin through molecular genetic analysis. Methods Twelve patients with choriocarcinoma, who had experienced surgery prior to chemotherapy were enrolled in this study. All 12 cases were diagnosed pathologically as choriocarcinoma. Peripheral venous blood samples and formalin-fixed paraffin-embedded blocks of choriocarcinoma tissue microdissected from haematoxylin and eosin-stained sections of tissue by microdissection method were available from the patient and (or) her husband. DNA was then prepared from the couples' blood samples and choriocarcinoma tissue by using standard techniques. PCR amplification and fluorescent microsatellite genotyping were performed by using DNA from the couples and captured choriocarcinoma tissues. The genetic contributions to the choriocarcinoma tissue were determined by comparing the fragments of genes from the choriocarcinoma tissue to those from blood samples of the couples. Results The primary lesion was ovary in 7 cases, but only 4 of them had the maternal contribution, indicating a non-gestational origin; the other three were gestational choriocarcinoma. The primary lesion was uterus in 5 cases, which were all gestational choriocarcinoma confirmed by genetic analyses. The causative pregnancies of the 8 cases with gestational choriocarcinoma were identified as androgenetic complete hydatidiform mole (AnCHM) in six cases and normal pregnancies in two cases, respectively. Conclusion Microsatellite polymorphism analysis is a molecular approach for distinguishing the non-gestational choriocarcinoma from the gestational one, and also be used to identify the causative pregnancy of gestational choriocarcinoma.

Loss of heterozygosity on multiple chromosomes in patients with esophageal cancer and its clinical significance / 中华检验医学杂志

Objective To investigate the loss of heterozygosity at 17 microsatellites of 10 chromosome arms in 68 resected specimens of esophageal cancer, and the relationship to the clinicopathological phenotypes of patients. Methods 68 tumor specimens (20 well-differentiated squamous carcinomas, 30 moderately differentiated carcinomas and 18 poorly differentiated carcinomas) and their matched blood samples were analyzed for LOH at 17 microsatellites by using PCR and fluorescence-based DNA sequencing technology, and the association of LOH with the clinicopathological phenotypes of patients was compared statistically. Results The lowest detection frequency of LOH in our subjects was observed at D8S261 with 33. 3%, and the highest frequency was at D9S125 with 85. 2%. There were 12 markers with the frequency of LOH higher than 50.0%, and 3 markers (D3S1597, D3S1285 and D9S125) with the frequency higher than 75. 0%. There was a significant difference in the frequency of LOH at D9S111 and D13S153 between tumors with different histological grades. LOH at D9S111 was observed in 2 of 12 tumors with well differentiation in 14 of 20 tumors with moderate differentiation, and in 14 of 16 tumors with poor differentiation. LOH at DI3S153 was observed in 2 of 8 tumors with well differentiation, in 12 of 28 tumors with moderate differentiation, and in 11 of 12 tumors with poor differentiation. There was a significant difference in the frequency of LOH at D8S261 between tumors with lymph node metastasis and without lymph node metastasis. LOH at D8S261 was found in 1 of 14 tumors with lymph node metastasis, and in 12 of 22 tumors without lymph node metastasis. Conclusions The widespread and frequent loss of heterozygosity may exist in esophageal cancer, and the candidate genes located in the site of frequent LOH may be involved in the development of this cancer; LOH at D9S11 and D13S153 are more commonly observed in the patients with higher histological grades, the tumors with LOH at D8S261 may have a low tendency to lymph node involvement.

Chromosome 1q21 contains genes linked to psoriasis vulgaris in Chinese Han population / 中华皮肤科杂志

Objective To study the responsible genes of psoriasis vulgaris on chromosome 1q21 in Chinese Han population.Methods Thirty-six families with psoriasis vulgaris,including 92 patients and 98 normal relatives,aged from 12 to 81 years with an average age at 44 years,were enrolled in this study.Blood samples were obtained from all the participants and subjected to DNA extraction.A genome scan was performed with eight microsatellites distributing over chromosome 1q21-1q23.1.Evidence for linkage disequilibrium was assessed with extended transmission disequilibrium test(ETDT)program and Genehunter software.Results Three short tandem repeat markers were found to be associated with psoriasis vulgaris.With Genehunter,evidence for linkage disequilibrium between D1S2345 and psoriasis was found with the NPL value being 1.735(P=0.0329).Moreover,ETDT revealed that the 97-bp allele of D1S2346 and 283-bp allele of D1S484 were preferentially delivered to affected descendants(P＜0.05).Conclusion Chromosome 1q21 contains genes associated with psoriasis vulgaris in Chinese Han population.

Study on the loss of heterozygosity of microsatellite DNA on chromosome 6 in human T-cell lymphoma / 肿瘤

Objective: To study the loss of heterozygosity (LOH) at 6 markers of microsatellite polymorphism on the chromosome 6 in T-cell lymphoma (TCL) to determine whether there existed tumor suppressor genes in the area related with the initiation and development of TCL. Methods: Six microsatellite polymorphism markers (D6S251, D6S275, D6S287, D6S267, D6S262, and D6S264) on the chromosome 6 were selected. We performed the amplification of microsatellite DNA with PCR, polyacrylamide gel electrophoresis and silver staining to detect LOH in 42 cases of T-cell lymphoma and the corresponding normal tissues. Results: LOH were detected at more than one locus in 13 out of 42 TCL patients (30.95%). Among the 6 loci, LOH occurred more frequently at D6S262 (10.3%), D6S287 (10.0%), and D6S267 (7.3%). No significant difference was found in LOH incidence between different clinicopathologic classifications (P > 0.05). Conclusion: The LOHs occur more frequently at markers D6S262, D6S287, and D6S267 on the chromosome 6q21 to 6q23. Cyclin C gene localized to chromosome 6q21 may be the candidate of tumor suppressor gene related with initiation and progression of TCL. Chromosome 6q21-6q23 may harbor a tumor suppressor locus which was related with TCL.

Clinical and pathologic characteristics of gastric cancer in elderly Korean patients in Korea / 대한내과학회지

BACKGROUND: Gastric cancer in elderly patients is one of the most important health issues in Korea, when considering its incidence and mortality rate. We have obtained the preliminary data concerning the diagnosis and treatment of gastric cancer in elderly people by analyzing the clinical and pathologic features. METHODS: We retrospectively analyzed 268 patients who were diagnosed with gastric cancer and who also underwent surgical procedures in Bundang Seoul National University Hospital from May 2003 to May 2005. The patients were divided into two groups: those aged or =65 (n=106). We compared the clinical and pathological characteristics between the older and younger groups. RESULTS: The elderly group had more patients with well differentiated carcinoma (11.8% vs. 33.0%, respectively, p=0.001) and the intestinal type (34.0% vs. 59.4%, respectively, p<0.001). The frequency of microsatellite instability-high (MSI-H) was higher in the elderly group (5.6% vs. 17%, respectively, p=0.010). There was no significant difference in the postoperative recovery time (p=0.374) and the operation-related complication rate between the two groups. CONCLUSIONS: Gastric cancer in elderly patients demonstrated more pathologic types that have a known favorable outcome when compared to the younger patient group. We should more frequently consider surgery for the elderly patient with operable gastric cancer because of they have similar postoperative recovery compared to the younger patients.

LOH and MSI of Fragile Histidine Triad Gene in laryngeal and hypopharyngeal carcinoma / 中国耳鼻咽喉头颈外科

0.05).⑥ The incidence of MSI at D3S1234,D3S4103,D3S1300 in recurring cases was 83.33 %,but the ratio of MSI inprimary cases was 30.77 %,the former was remarkablyhigher than the latter(P=0.004).CONCLUSION ①Microsatellite analysis showed that both LOH andMSI of FHIT gene existed in laryngeal carcinoma andhypopharyngeal carcinoma,the former was morecommon.② FHIT gene participates the developmenof laryngeal carcinoma and hypopharyngeal carcinoma and may be one of the candidate tumor suppressor genes.③ MSI of FHIT gene may be correlated with recurrence of laryngeal and hypopharyngeal carcinoma.

Microsatellite instability and abnormal mismatch repair in laryngeal squamous cell carcinoma / 中国耳鼻咽喉头颈外科

OBJECTIVE The aim of our study was to evaluate the significance of the frequency of microsatellite instability (MSI) and its relationship to mismatch repair gene (MMR) in laryngeal squamous cell carcinoma.METHODS We investigated the expression frequency and clinical significance of MSI and MMR in 50 laryngeal squamous cell carcinoma (LSCC) patients from Beijing Tongren Hospital. The status of MSI was evaluated using microdissection - polymerase chain reaction (PCR) - single strand length polymorphism (SSLP) - silver staining.Five markers on chromosomes 1p, 3p, 5q, 9p, 17p, which were adjacent to BCAR3 (breast cancer anti-estrogen resistance 3), FHIT, APC, CDKN2A (p16), TP53 respectively, were used. Two of the six components of MMR -hMLH1 and hMSH2- were investigated by an immunohistochemical approach because of the high frequency of their downregulation in head and neck tumors. RESULTS The informative case number of the five markers (D17S796, D3S3544, D5S656, D1S375, D9S162) were 44, 42, 45, 44 and 40 respectively. The incidence of MSI was lower than the frequency of loss of heterozygosity (LOH). The incidence of MSI on D17S796 (TP53)was 20.5% (9/44),on D3S3544 (FHIT) was 14.3 % (6/42), on D5S656 (APC) was 31.1% (14/45), on D1S375 (BCAR3) was 20.5 % (9/44), and on D9S162 (CDKN2A) was 15.0 % (6/40). Though there was no relationship between MSI status and age, gender, smoke history, tumor location, tumor differentiation and T stage (P＞0.05),there was a strong correlation between MSI and relapse condition (P＜0.01). Also, MSI status correlated with MMR expression to some degree (P＜0.01), but it was common for negative and positive staining of MMR to coexist on the same slide. CONCLUSION Microsatellite instability and abnormal mismatch repair may contribute to the carcinogenesis of a subset of laryngeal squamous cell carcinoma. Microsatellite instability may be a characteristic signal of tumor recurrence.

Heterozygosities of 735 microsatellite markers and background linkage disequilibrium in the Korean population

Suitability of a specific population for linkage disequilibrium mapping studies of complex traits may be assessed by investigating the background linkage disequilibrium (BLD). We are unaware of studies for quantifying the degree of BLD in the Korean population, although the population may be a good candidate for mapping of complex trait genes through whole-genome association studies. It is useful to investigate the properties of genetic isolates in East Asia and to compare them to genetic isolates in Europe. We analyzed the extent of BLD in the Korean population using 735 microsatellite markers and compared the results with the Icelander population, which is one of the European expanded genetic isolates. The Korean population exhibited a level of BLD comparable with the Icelander population. The inference of population structure using the model with admixture showed that each individual has allele copies originating from K populations in equal proportions. Therefore, we believe that factors other than genetic distance, such as recent admixture, have not contributed to the level of BLD. Our results showed that the Korean population, which is an expanded population with no evidence of admixture, has a BLD level comparable with the Icelander population. Therefore, the Korean population can be used for fine mapping of either complex traits or monogenic diseases.

Microsatellite Instability and Mismatch Repair Protein (hMLH1, hMSH2) Expression in Intrahepatic Cholangiocarcinoma

BACKGROUND: To clarify the role of the mismatch repair (MMR) system in the carcinogenesis of intrahepatic cholangiocarcinoma (ICC), we investigated the microsatellite instability (MSI) status and MMR protein expression in ICC. METHODS: Thirty-six cases of ICCs were examined by microsatellite analysis for 55 markers that encompassed all of the chromosomal arms and BAT26. An immunohistochemical study for hMLH1 and hMSH2 was also performed. RESULTS: Widespread MSI (MSI-H) accompanied with a loss of hMLH1 expression was found in one case (2.8%). This MSI-H case was an adenosquamous carcinoma showing intraductal tubulopapillary adenocarcinoma and invasive adenosquamous carcinoma component. Loss of hMLH1 was noted in both components while the frequency and shifted band patterns of MSI were not identical between the components. Another 10 ICCs (27.8%) revealed low level MSI with preserved MMR gene expression. CONCLUSIONS: Our data suggested that a genetic defect in the MMR system and MSI is not a major pathway in the carcinogenesis of ICC.

Hereditary neuropathy with liability to pressure palsies (HNPP) patients of Korean ancestry with chromosome 17p11.2-p12 deletion

Hereditary neuropathy with liability to pressure palsies (HNPP) is an autosomal dominant inherited disorder characterized by recurrent pressure palsies. Most HNPP patients have a 1.5 mb deletion in chromosome 17p11.2-p12. The present study aimed at evaluating the deletion of the 17p11.2-p12 region in Korean subjects with families exhibiting HNPP phenotype, and to determine the clinical, electrophysiological and morphological aspects specifically associated with this deletion in HNPP patients. By genotyping six microsatellite markers (D17S921, D17S955, D17S1358, D17S839, D17S122 and D17S261), HNPP with the deletion was observed in 79% (19 of 24) of HNPP families. Nerve conduction studies were performed in 35 HNPP patients from these 19 families. The observed HNPP deletion frequency in Koreans is consistent with findings in other populations. Disease onset occurred at a significantly earlier age in patients with recurrent pressure palsies than in those with a single attack (P<0.01). Nerve conduction studies demonstrated diffuse mild to moderate slowing of nerve conduction velocities that were worse over the common entrapment sites, regardless of the clinical manifestations. A long duration of compound muscle action potentials without a conduction block or a temporal dispersion is a characteristic of this disease. A sural nerve biopsy with teasing was performed in four patients, and tomacula of the myelin sheath was found in 56.4%. Our findings appear to support the existence of a phenotype/genotype correlation in HNPP patients of Korean ancestry with the deletion, and suggest that HNPP patients with earlier symptom onset face an increased chance of having recurrent attacks.