Regulatory effect of small nuclear ribonucleoprotein-associated protein B on proliferation and metastasis of liver cancer cells / 中华肝脏病杂志

Objective: To study the expression and effect of small nuclear ribonucleoprotein-associated protein B (SNRPB) on proliferation and metastasis of liver cancer tissues and cells. Methods: The bioinformatics database starBase v3.0 and GEPIA were used to analyze the expression of SNRPB in liver cancer tissue and normal liver tissue, as well as the survival and prognosis of liver cancer patients. The expression of SNRPB mRNA and protein in liver cancer cell lines were analyzed by qRT-PCR and Western blot. RNA interference technique (siRNA) was used to determine SNRPB protein expression down-regulation. The proliferation effect on hepatocellular carcinoma cells was observed by MTT assay. Transwell invasion and migration assay was used to detect the changes in the metastatic ability of liver cancer cells after SNRPB down-regulation. Western blot was used to detect the changes of epithelial mesenchymal transition (EMT) markers in liver cancer cells after down-regulation of SNRPB expression. Data were compared between two groups and multiple groups using t-test and analysis of variance. Results: The expression of SNRPB was significantly higher in liver cancer tissue than normal liver tissue, and its expression level was correlated with the prognosis of liver cancer patients. Compared with the immortalized hepatocyte LO(2), the expression of SNRPB was significantly increased in the liver cancer cells (P < 0.01). siRNA-SNRPB had significantly inhibited the expression of SNRPB mRNA and protein in liver cancer cells. MTT results showed that the absorbance value was lower in SNRPB knockdown group than negative control group, and the difference at 96 h after transfection was most significant (P < 0.01). Transwell assay results showed that compared with the negative control group, the SNRPB knockdown group (MHCC-97H: 121.27 ± 8.12 vs. 46.38 ± 7.54; Huh7: 126.50 ± 6.98 vs. 41.10 ± 8.01) invasion and migration (MHCC-97H: 125.20 ± 4.77 vs. 43.18 ± 7.32; Huh7: 132.22 ± 8.21 vs. 38.00 ± 6.78) ability was significantly reduced (P < 0.01) in liver cancer cells. Western blot showed that the expression level of epithelial phenotype marker E-cadherin was decreased after down-regulation of SNRPB, while the expression levels of mesenchymal phenotype markers N-cadherin and vimentin was increased, suggesting that down-regulation of SNRPB inhibited EMT in liver cancer cells. Conclusion: SNRPB expression is significantly increased in liver cancer tissues and cells, and it is involved in regulating the proliferation, metastasis and EMT of liver cancer cells.

Genetics of Prader-Willi syndrome and Prader-Will-Like syndrome

The Prader-Willi syndrome (PWS) is a human imprinting disorder resulting from genomic alterations that inactivate imprinted, paternally expressed genes in human chromosome region 15q11-q13. This genetic condition appears to be a contiguous gene syndrome caused by the loss of at least 2 of a number of genes expressed exclusively from the paternal allele, including SNRPN, MKRN3, MAGEL2, NDN and several snoRNAs, but it is not yet well known which specific genes in this region are associated with this syndrome. Prader-Will-Like syndrome (PWLS) share features of the PWS phenotype and the gene functions disrupted in PWLS are likely to lie in genetic pathways that are important for the development of PWS phenotype. However, the genetic basis of these rare disorders differs and the absence of a correct diagnosis may worsen the prognosis of these individuals due to the endocrine-metabolic malfunctioning associated with the PWS. Therefore, clinicians face a challenge in determining when to request the specific molecular test used to identify patients with classical PWS because the signs and symptoms of PWS are common to other syndromes such as PWLS. This review aims to provide an overview of current knowledge relating to the genetics of PWS and PWLS, with an emphasis on identification of patients that may benefit from further investigation and genetic screening.

Genetics of Prader-Willi syndrome and Prader-Will-Like syndrome

The Prader-Willi syndrome (PWS) is a human imprinting disorder resulting from genomic alterations that inactivate imprinted, paternally expressed genes in human chromosome region 15q11-q13. This genetic condition appears to be a contiguous gene syndrome caused by the loss of at least 2 of a number of genes expressed exclusively from the paternal allele, including SNRPN, MKRN3, MAGEL2, NDN and several snoRNAs, but it is not yet well known which specific genes in this region are associated with this syndrome. Prader-Will-Like syndrome (PWLS) share features of the PWS phenotype and the gene functions disrupted in PWLS are likely to lie in genetic pathways that are important for the development of PWS phenotype. However, the genetic basis of these rare disorders differs and the absence of a correct diagnosis may worsen the prognosis of these individuals due to the endocrine-metabolic malfunctioning associated with the PWS. Therefore, clinicians face a challenge in determining when to request the specific molecular test used to identify patients with classical PWS because the signs and symptoms of PWS are common to other syndromes such as PWLS. This review aims to provide an overview of current knowledge relating to the genetics of PWS and PWLS, with an emphasis on identification of patients that may benefit from further investigation and genetic screening.

Evaluating Anti-SmD1-amino-acid 83-119 Peptide Reactivity in Children with Systemic Lupus Erythematosus and Other Immunological Diseases / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>SmD1-amino-acid 83-119 peptide (SmD183-119) is the major epitope of Smith (Sm) antigen, which is specific for adult systemic lupus erythematosus (SLE). The anti-SmD183-119 antibody has exhibited higher sensitivity and specificity than anti-Sm antibody in diagnosing adult SLE. However, the utility of anti-SmD183-119antibodies remains unclear in children with SLE (cSLE). This study aimed to assess the characteristics of anti-SmD183-119antibody in the diagnosis of cSLE.</p><p><b>METHODS</b>Samples from 242 children with different rheumatological and immunological disorders, including autoimmune diseases (SLE [n = 46] and ankylosing spondylitis [AS, n = 11]), nonautoimmune diseases (Henoch-Schonlein purpura [HSP, n = 60], idiopathic thrombocytopenia purpura [n = 27], hematuria [n = 59], and arthralgia [n = 39]) were collected from Shanghai Children's Medical Center from March 6, 2012 to February 27, 2014. Seventy age- and sex-matched patients were enrolled in this study as the negative controls. All the patients' sera were analyzed for the anti-SmD183-119, anti-Sm, anti-U1-nRNP, anti-double-stranded DNA (dsDNA), anti-nucleosome, anti-SSA/Ro60, anti-SSA/Ro52, anti-SSB, anti-Scl-70, and anti-histone antibodies using the immunoblotting assay. The differences in sensitivity and specificity between anti-SmD183-119 and anti-Sm antibodies were compared by Chi-square test. The correlations between anti-SmD183-119and other auto-antibodies were analyzed using the Spearman's correlation analysis. A value of P< 0.05 was considered statistically significant.</p><p><b>RESULTS</b>Thirty-six out of 46 patients with cSLE were found to be positive for anti-SmD183-119, while 12 patients from the cSLE cohort were found to be positive for anti-Sm. Compared to cSLE, it has been shown that anti-SmD183-119 was only detected in 27.3% of patients with AS and 16.7% of patients with HSP. In comparison with anti-Sm, it has been demonstrated that anti-SmD183-119 had a higher sensitivity (78.3% vs. 26.1%, χ2 = 25.1, P< 0.05) and a lower specificity (90.8% vs. 100%, χ2 = 13.6, P< 0.05) in the diagnosis of cSLE. Further analysis revealed that anti-SmD183-119antibodies were positively correlated with anti-dsDNA, anti-nucleosome, and anti-histone antibodies in cSLE. Moreover, it has been clearly shown that anti-SmD183-119 was more sensitive than anti-Sm in discriminating autoimmune diseases from nonautoimmune disorders in patients with arthralgia or hematuria.</p><p><b>CONCLUSIONS</b>Measurement of anti-SmD183-119in patients with cSLE has a higher sensitivity and a marginally lower specificity than anti-Sm. It has been suggested that inclusion of anti-SmD183-119testing in the integrated laboratory diagnosis of cSLE may significantly improve the overall sensitivity in child populations.</p>

Genotyping and parental related methylation of SNRPN gene rs220030 / 法医学杂志

OBJECTIVE@#To establish two methods by denaturing gradient gel electrophoresis (DGGE) and pyrosequencing for genotyping rs220030 (a SNP in the promoter region of small nuclear ribonucleoprotein polypeptide N, SNRPN). To establish an analytical technique for detecting CpG methylation status by pyrosequencing and to further investigate the feasibility of applying rs220030 to the determination of parental origin allele.@*METHODS@#The rs220030 of 97 blood samples from individuals of Shanghai Han population were genotyped by DGGE, meanwhile the rs220030 of 25 blood samples of them were genotyped by pyrosequencing to compare the two methods in genotyping SNP. Pyrosequencing united bisulfite conversion method was applied to detect CpG methylation status of region upstream rs220030 of two random blood genealogical samples and investigate whether the methylation status was parental related.@*RESULTS@#The rs220030 genotyping results of 97 blood samples detected by DGGE were 20 C homozygote, 29 T homozygote, and 48 C/T heterozygote. Twenty-five blood samples genotyped by pyrosequencing showed the same result with DGGE. The CpG methylation status of region upstream rs220030 of the child was similar to the mother.@*CONCLUSION@#Compared with DGGE, pyrosequencing is more accurate, convenient, and suitable for large samples and high throughput SNP genotyping. Pyrosequencing united bisulfite conversion can be used to detect CpG methylation status precisely. It is feasible to apply rs220030 to parental origin allele determination.

Polymorphism study of small nuclear ribonucleoprotein polypeptide N gene rs220030 by DGGE / 法医学杂志

OBJECTIVE@#To analyze the polymorphism of rs220030, a SNP which is located in the promoter region of small nuclear ribonucleoprotein polypeptide N (SNRPN) gene in the Chinese Han population and to obtain the data of population genetics.@*METHODS@#The denaturing gradient gel electrophoresis (DGGE) method was applied to detect the polymorphism of rs220030 in 100 unrelated and healthy individuals from the Shanghai Han population. The genotyping result of this SNP was confirmed by TaqMan assay in some typical samples.@*RESULTS@#DGGE results showed 4 bands for CT heterozygote, and 1 band for CC or TT homozygote, and those results were confirmed by The TaqMan SNP genotyping assays. Genotyping results showed 34 individuals with CC, 41 with CT and 25 with TT of rs220030. The allele frequencies for C and T were 0.545 and 0.455, respectively. H was 0.500, PIC was 0.373, DP was 0.654, and PE was 0.186. The distribution of genotype frequencies were in Hardy-Weinberg equilibrium.@*CONCLUSION@#DGGE is a quick and effective method in the analysis of SNP polymorphism in small population. Statistical parameters of rs220030 for forensic evaluation meet the requirements for forensic identification and paternity testing.

Mutation analysis of SMN gene in a patient and his family with spinal muscular atrophy / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To perform mutation analysis and describe the genotype of the SMN gene in a patient with spinal muscular atrophy (SMA) and his family.</p><p><b>METHODS</b>Deletion analysis of the SMN1 exon 7 by conventional PCR-restriction fragment length polymorphism (RFLP) and allele-specific PCR, and gene dosage of SMN1 and SMN2 by multiplex ligation-dependent probe amplification (MLPA) were performed for the patient and his parents; reverse transcriptase (RT)-PCR and sequencing were performed for the patient. To determine whether the SMN variant was exclusive to transcripts derived from SMN1, the RT-PCR product of the patient was subcloned and multiple clones were sequenced directly; PCR of SMN exon 5 from the genomic DNA of the parents and direct sequencing were performed to confirm the mutation.</p><p><b>RESULTS</b>In SMN1 exon 7 deletion analysis, no homozygous deletion of the SMN1 was observed in the family; the gene dosage analysis by MLPA showed that the patient had 1 copy of SMN1 and 1 copy of SMN2 his father had 2 copies of SMN1 and 2 copies of SMN2, and his mother had 1 copy of SMN1 and no SMN2. A previously unreported missense mutation of S230L was identified from the patient and this mutation was also found in his father.</p><p><b>CONCLUSION</b>A novel missense mutation of S230L was identified in the SMA family and the genotype of the family members were investigated.</p>

Methylation Patterns of Small Nuclear Ribonucleoprotein Polypeptide N (SNRPN) Related to the Germ Cell Differentiation of Human Germ Cell Tumors

BACKGROUND: The histogenesis and interrelationship of the various types of germ cell tumors (GCTs) have been proposed. Dysgerminoma/seminoma (D/S) is a primitive GCT that has not acquired the potential for further differentiation, whereas other types of GCTs are in a dynamic process of differentiation towards a somatic or extraembryonal direction. A primordial germ cell giving rise to a GCT undergoes a developmentally regulated erasure and resetting of imprinted genes, but changes in the imprinting pattern in GCTs as the tumor differentiates have not been well defined. We aimed to investigate the changes of the SNRPN methylation pattern between the germinomas and non-germinomatous GCTs, as compared with the somatic methylation pattern. METHODS: We used formalin-fixed paraffin-embedded tissue sections of 97 GCTs (18 Ds, 21 Ss, 17 yolk sac tumors (YSTs), 19 immature teratomas, and 22 mature teratomas). DNA methylation was evaluated after bisulfite modification, PCR amplification, and restriction enzyme digestion. RESULTS: The SNRPN methylation pattern was changed in 53/74 (71.6%) of GCTs as non-somatic patterns. There were significant differences in the methylation pattern between the germinomas and non-germinomatous GCTs, the GCTs being frequently hypo- methylated in Ds/Ss (73.3%), in contrast to the frequent hypermethylation seen in the YSTs and teratomas (47.7%, p<0.05). CONCLUSIONS: The methylation status of an imprinting gene may be involved in the mechanism causing cellular differentiation and tumorigenesis of GCTs.

Molecular markers for diagnosis of Prader-Willi syndrome in thai patients by fish.

Paternal microdeletion of chromosome 15 at q11-q13 has been reported in 75% of Prader-Willi syndrome (PWS) patients in western countries. Diagnosis of PWS in Thailand is mainly based on clinical observation and, in some cases, confirmed by conventional cytogenetic analysis. Loss of a tiny segment in this region (microdeletion) has made it difficult to discriminate from the normal karyotype. An attempt to solve this problem has been made by using a high resolution chromosome culture. However, this method is a tedious and time-consuming technique which is suitable for only experienced cytogeneticists. We report molecular cytogenetic analysis for PWS in Thai patients using FISH in addition to standard GTG- banding chromosome analysis. Nine Thai patients clinically diagnosed or with a suspicion of PWS were investigated. The FISH probes consist of the region-specific probes (SNRPN or D15S10 probe) and two chromosome 15-specific control probes (D15Z1 centromeric and PML chromosome 15 long arm probe). Bright field and FISH programs of an automatic karyotyper were applied to facilitate the efficiency of the chromosome analysis. We found that 2 out of 9 patients showed a deletion at 15q11-q13 region by standard GTG chromosome analysis while 4 out of 9 patients showed a delation in this region by FISH. Consistent losing of SNRPN and D15S10 signals in FISH was observed in these patients. This forty-four per cent deletion is considerably lower than those reported from western countries. We propose that DNA methylation at SNRPN promoter as well as structural abnormalities in other chromosome regions might also play a role in the etiology of this disorder in Thais, which should be investigated further.

Prader-Willi syndrome and genomic imprinting / 中华儿科杂志

<p><b>OBJECTIVE</b>Prader-Willi syndrome (PWS) is an example of a human genetic disorder that involves imprinting genes on the proximal long arm of chromosome 15 and SNRPN gene as a candidate gene for this syndrome. The purpose of this study was to show the molecular genetic defects and genomic imprinting basis in Chinese PWS patients and to evaluate the clinical applications of a differential diagnostic test for PWS.</p><p><b>METHODS</b>Fluorescence in situ hybridization (FISH) and methylation-specific PCR (MSPCR) techniques were applied for 4 clinically suspected PWS patients. Using three probes, including SNRPN probe for identification of the critical locus in PWS region, D15Z1 and PML control probes for identification of the 15p arm and 15q arm, the authors detected the deletions 15q in PWS. MSPCR was based on sodium bisulfite treatment of DNA and PCR primers specific for the maternal and paternal allele.</p><p><b>RESULTS</b>When hybridized with mixed probes, it was found in 2 patients that the central specific signal was absent, but both the flanking control signals were retained, indicating SNRPN gene deletion of chromosome 15q11-13. Bisulfite-modified DNA from all PWS children amplified with methylated allele-specific primer pair showed only maternal 131bp PCR product, indicating the maternal uniparental disomy (UPD15).</p><p><b>CONCLUSION</b>Genomic imprinting plays an important role in the molecular pathogenesis of PWS that caused by paternal microdeletions of 15q11-q13 or maternal UPD of chromosome 15. The basic defect seemed to be an absence of function of PWS genes that are normally expressed only from the paternal chromosome 15. MSPCR is a rapid and simple PCR-based assay compared with other cyto-molecular tests and its results were consistent with the clinical diagnosis of PWS, so it seems to be a reliable diagnostic method for PWS patients who show abnormal methylation at SNRPN. The genetic differential tests for PWS are important in determining familial recurrence risk.</p>

Clinical Characteristics and Genetic Analysis of Prader-Willi Syndrome

PURPOSE: Prader-Willi syndrome(PWS) is a complex disorder affecting multisystems with characteristic clinical features. Its genetic basis is an expression defect in the paternally derived chromosome 15q11-q13. We analyzed the clinical features and genetic basis of PWS patients for early detection and treatment. METHODS: We retrospectively studied 24 patients with PWS in Department of Pediatrics, Samsung Medical Center, from September 1997 to September 2001. We performed cytogenetic and molecular genetic techniques using high resolution GTG banding techniques, fluorescent in situ hybridization and methylation-specific PCR for CpG island of SNRPN gene region. RESULTS: The average birth weight of PWS patients was 2.67+/-0.47 kg and median age at diagnosis was 1.3 years. The average height and weight of PWS patients under one year at diagnostic time were located in a 3-10 percentile relatively, and a rapid weight gain was seen between two and six years. Feeding problems in infancy and neonatal hypotonia were the two most consistently positive major criteria in over 95% of the patients. In 18 of the 24 cases(75%), deletion of chromosome 15q11-q13 was demonstrated and one case among 18 had an unbalanced 14;15 translocation. In four cases without any cytogenetic abnormality, it may be considered as maternal uniparental disomy and the rest showed another findings. CONCLUSION: We suggest diagnostic testing for PWS in all infants/neonates with unexplained feeding problems and hypotonia. It is necessary for clinically suspicious patients to undergo an early genetic test. As the genetic basis of PWS was heterogenous and complex, further study is required.

A Study of Prader-Willi Syndrome and Angelman Syndrome with the Deletion of Same Loci in 15 Chromosome

PURPOSE: In general, genetic disorders have the numerical or structural abnormalities of chromosome. There are clinically two different disorders, Prader-Willi syndrome(PWS) and Angelman syndrome(AS), which have the deletion of specific region of 15 chromosome originated from father or mother by genetic imprinting phenomenon. We reported the results of genetic study including DNA methylation analysis and fluorescence in situ hybridization(FISH), in addition to clinical findings. METHODS: We studied 20 patients of PWS and AS diagnosed in pediatric department of Asan Medical Center from 1992 Feb. to 2001 Apr., retrospectively. We analyzed the clinical manifestations of the disorders and performed cytogenetic studies from the peripheral blood. And we the methylation pattern and FISH, using the probe for single nucleotide ribonucleoprotein N(SNRPN) locus within the Prader-Willi/Angelman region (15q11-q13). RESULTS: Among 16 patients of PWS, the age at initial visit was from 3 days to 12 years and the male to female ratio was 1.67:1. Seven patients had the history of intrauterine growth retardation or fetal distress. The chief complaints at initial presentation were classified on age. Under 3 years(n=10), there were hypotonia(4), development delay (3), feeding difficulties(2), and tachycardia(1). Above 3 years(n=6), we found short stature(2), respiratory difficulty(1), seizure(1), obesity(1), and undescended testes(1). DNA methylation study showed the methylation of 15 chromosome originated from paternal chromosome and the microdeletion by FISH was detected in all 12 among 12 patients (100%). In AS(n=4), the sex ratio(M:F) was 3:1 and age at presentation was from 15 months to 6 years. The important sign was severe developmental delay in all patients, combined with mental retardation in one case. Other clinical manifestations were depigmentation of skin and hair(4), prognathism(3), seizure(3), frequent laughing(2), undescended testes(1), hypotonia(1), and hyperactivity(1). FISH study was performed and showed the microdeletion of 15 chromosome in all 4 patients. CONCLUSION: We studied the clinically two different disorders, PWS and AS, with the deletion of same region of 15 chromosome and reported the results of the clinical and genetic analysis based on clinical findings and DNA analysis and FISH study, respectively.

A Case of Mosaicism in Prader-Willi Syndrome:Detection Using Fluorescent in Situ Hybridization / 대한소아내분비학회지

Prader-Willi syndrome is caused by absence of paternal contribution of chromosome region 15q11-q13. PWS is clinically suspected and can be confirmed by laboratory tests. It is accepted that DNA methylation analysis is very useful screening test and FISH with specific probe can be used for deletion detection for PWS. In clinically suspected PWS patients, we conducted two genetic tests, FISH with SNRPN probe and SNRPN expression study with RT-PCR. We found discordance in one patient. This PWS male presented with severe obesity, hypogonadism and typical appearance with the history of neonatal hypotonia and feeding problems. The FISH showed the microdeletion in 15q11-q13 as expected, but the result of SNRPN expression was positive. We reviewed FISH and observed normal cells without deletion. Methylation analysis is not sensitive enough to identify cases of mosaic PWS. So, when the molecular screening is negative, precise clinical examination is essential and other cytogenetic analysis like FISH should be combined.

The Usefulness of Fluorescence in Situ Hybridization(FISH) in the Diagnosis of Prader-Willi Syndrome

PURPOSE: To detect microdeletion of 15q11-13 region, high resolution cytogenetic analysis or FISH with probe at Prader-Willi syndrome region can be used. We tried to evaluate whether FISH with SNRPN is a more effective method than G-banding microscope in the diagnosis of Prader-Willi syndrome. MEHTODS: Peripheral blood sampling was done on five patients who we suspected of Prader-Willi syndrome clinically and lymphocytes from peripheral blood sampling were cultured. G-banding microscope was used to detect the microdeletion in chromosome 15 and FISH with SNRPN probe was used to detect signal defect in band q11-q13 in chromosome 15. RESULTS: There was a fluorescent signal defect in band 15 q11-q13 in one of chromosome 15 in 4 children with FISH method and only one patient was diagnosed with Prader-Willi syndrome with G-banding microscope. CONCLUSION: FISH analysis is more accurate, objective, and time saving than G-banding microscope, therefore it can be considered as a more adequate screening test for the diagnosis of Prader-Willi syndrome.

Comparison of counter immunoelectrophoresis with immunoblotting for detection of anti-extractable nuclear antigen antibodies in systemic lupus erythematosus.

Anti-extractable nuclear antigen (ENA) antibodies were assayed by counter immunoelectrophoresis (CIE) and immunoblotting in patients with systemic lupus erythematosus (SLE). We found the two methods showed good concordance rates, the lowest being 67% for anti-SS-A. Immunoblotting was more sensitive in detecting anti-Sm, anti-SS-B and anti-PCNA (proliferating cell nuclear antigen); CIE was more sensitive for anti-nRNP and anti-SS-A. Overall, the prevalence of these anti-ENA antibodies in SLE was increased by 9-20% if immunoblotting was used in addition to CIE. Sera specific for the 52 kDa peptide of the SS-A antigen (anti-52kDa SS-A) were better detected by immunoblotting. Anti-PCNA antibody was found in 6.3% of SLE patients and was associated with active disease and hemolytic anemia. The positive rate of anti-Sm was 9% by CIE and 23.7% by immunoblotting and this antibody was a specific marker for SLE using either method. It was concluded that using immunoblotting in addition to CIE, the overall sensitivity of detection of anti-ENA antibodies in SLE was increased and clinically useful antibodies such as anti-52kDa SS-A and anti-PCNA could be detected.

Molecular Diagnostic Test for Prader-Willi Syndrome with SNRPN Expression / 대한소아내분비학회지

PURPOSE: Prader-Willi Syndrome(PWS) is caused by absence of paternal contributions of the chromosome region 15q11-q13. To detact this region, high resolutional cytogenetic analysis, FISH with probe at PWS critical region or microsatellite polymorphism can be used. The gene for the small nuclear ribonucleoprotein polypeptide N(SNRPN) is not expressed in patients with PWS. We conducted molecular analysis with RT-PCR with SNRPN primers to find out more useful diagnostic tool in PWS. METHODS: Four patients with obesity and other characteristics of PWS were studied. The exprssion of SNRPN and control gene were studed by RT-PCR from peripheral lymphocytes. RESULTS :The SNRPN expression in reverse transcribed RNA from blood were easily detected in normal control but not in patients with suspected Parder-Willi Syndrome. CONCLUSION: We conclude that SNRPN expression study is a useful diagnostic method for detection of Prader-Willi Syndrome.

The prevalence of antinuclear, anti-dsDNA, anti-Sm and anti-RNP antibodies in a group of healthy blood donors.

We studied the prevalence of antinuclear (ANA), anti-double stranded DNA (dsDNA), anti-Sm and anti-RNP antibodies in a group of 93 blood donors (age range: 18-58 years). Antinuclear and anti-ds DNA antibodies were detected by immunofluorescence (IF) using HEp2 cells and Crithidia luciliae as substrates, respectively, while anti-Sm and anti-RNP antibodies were assayed by ELISA. ANA was found in 6.5% while anti-dsDNA antibodies were not detected in any of the subjects. The 98th percentile was used as cut off where values greater than 0.651 for anti-Sm and 0.601 for anti-RNP antibodies were taken to be positive. This gives a frequency of 1.1% for both antibodies. There was no significant association of antibody positivity with sex or race. We conclude that certain autoantibodies are present in low titres in the normal Malaysian Individuals, at a different frequency compared to other studies probably due to genetic, ethic or environmental factors.