[Clinical characteristics and genetic analysis of a Chinese pedigree affected with Alström syndrome].

OBJECTIVE: To explore the clinical characteristics and genetic etiology of a Chinese pedigree affected with Alström syndrome. METHODS: A pedigree with 5 members affected with Alström syndrome who had visited the First Affiliated Hospital of Zhengzhou University in February 2021 was selected as the study subject. Clinical data of the pedigree were collected, and peripheral venous blood samples were collected for the extraction of genomic DNA. Genetic testing was carried out for the eldest daughter and third son through whole exome sequencing (WES). Candidate variant was verified by Sanger sequencing and bioinformatic analysis. RESULTS: The eldest daughter (14 years old) and the third son (11 years old) both had congenital nystagmus, amblyopia, growth retardation and type 2 diabetes. WES revealed that both had harbored homozygous c.3538A>T (p.Lys1180*) variant of the ALMS1 gene. Sanger sequencing confirmed that the father, mother, and second daughter were all heterozygous carriers. Based on the Guidelines for Genetic Variation and the Technical Standards for Interpretation and Reporting of Primary Copy Number Variations, the variant was predicted as pathogenic (PVS1+PM2_Supporting+PP4). CONCLUSION: The homozygous c.3538A>T (p.Lys1180*) variant of the ALSM1 gene probably underlay the Alström syndrome in this pedigree, which has provided a reference for the clinical treatment.

[Genetic analysis of a pregnant woman with moderate intellectual disability due to variant of DLG4 gene].

OBJECTIVE: To carry out genetic testing and prenatal diagnosis for a woman featuring moderate intellectual disability (ID). METHODS: The patient had presented at the First Affiliated Hospital of Zhengzhou University on April 28, 2021. With informed consent, peripheral blood and amniotic fluid samples were collected for the extraction of genomic DNA. Pathogenic copy number variations (CNVs) were detected with CNV-seq, and single gene variants were detected by whole exome sequencing (WES) and Sanger sequencing. Candidate variant was verified by Sanger sequencing, and CNV-seq and multiplex ligation-dependent probe amplification (MLPA) were used to detect fetal CNVs. RESULTS: The 23-year-old woman had moderate ID, sideway walking, and unstable holding. Ultrasonography at 18+3 weeks' gestation had revealed no fetal abnormality. No pathogenic CNV was detected in the woman by CNV-Seq, while WES revealed that she has harbored a heterozygous c.1675C>T (p.Arg559*) variant of the DLG4 gene, which was verified by Sanger sequencing. Based on guidelines from the American College of Medical Genetics and Genomics, the variant was predicted to be likely pathogenic (PVS1+PM2_supporting). Sanger sequencing has confirmed that the fetus has inherited this variant, and CNV-Seq also revealed that that fetus has harbored a 0.1 Mb heterozygous deletion at Xp21.1, which has encompassed the DMD gene, and the result was verified by MLPA. CONCLUSION: The heterozygous c.1675C>T variant of the DLG4 gene probably underlay the mental retardation in this woman, and her fetus was found to harbor the same variant in addition with deletion of the DMD gene, which may predispose to ID type 62.

[Genetic diagnosis of 3 families with choroideremia].

OBJECTIVE: To analyze the clinical manifestations and causative gene variants of the choroideremia patients, and to help the patients bedifferential diagnosed by whole exome sequencing and provide theoretical basis for their genetic counseling. METHODS: Clinical data of 3 families were collected and genomic DNA was extracted respectively from peripheral blood of patients and related subjects. Exome targeted sequencing was used to screen suspicious gene mutations. Sanger sequencing and quantitative PCR were used to verify the candidate mutations and investigate the mutation carrying status of other members of the family. The candidate mutations were searched through HGMD and PubMed databases for the pathogenicity reports, and the pathogenicity of candidate mutations was judged according to a joint consensus recommendation of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology. RESULTS: The proband of family 1 is c.1584_1587del (p.Val529Hisfs*6) variant hemizygote, whose daughter carries c.1584_1587del (p.Val529Hisfs*6) heterozygous variation. The proband of family 2 is a hemizygote with deletion of exons 10 to 15 (E10-15del), and her mother and sister carry the E10-15del heterozygous variation. In family 3, the proband is c.544delT (p.Cys182Valfs*14) variant hemizygote, and his mother is c.544delT (p.Cys182Valfs*14) heterozygote, but the father do not detect this variant. All the 3 families were detected pathogenic gene variations of CHM, two of which were known pathogenic variation and one of which was novel CHM gene c.544delT (p.C182Vfs*14) in this study. The c.544delT frameshift mutation of CHM gene can lead to the premature termination of the product protein translation and nonfunctioning protein. It is a pathogenic mutation according to ACMG guidelines. CONCLUSION: The findings of this study expand the gene variation spectrum of choroideremia.

[Genetic analysis and prenatal diagnosis of a Chinese pedigree affected with microphthalmia/coloboma and skeletal dysplasia syndrome due to variant of MAB21L2 gene].

OBJECTIVE: To explore the genetic basis for a Chinese pedigree affected with microphthalmia. METHODS: Clinical data of the proband was collected. Whole exome sequencing (WES) was carried out to screen potential pathogenic variants in the proband. Candidate variant was verified by Sanger sequencing of the proband and his family members. Pathogenicity of the variant was predicted by searching the PubMed database and bioinformatic analysis. Sanger sequencing of amniotic fluid sample was carried out for prenatal diagnosis. RESULTS: The proband and his father were found to harbor a heterozygous c.151C>G (p.R51G) variant of the MAB21L2 gene. The same variant was not found in his mother and grandparents. Based on the guidelines of American College of Medical Genetics, the c.151C>G (p.R51G) variant was predicted as likely pathogenic. CONCLUSION: The c.151C>G (p.R51G) variant of the MAB21L2 gene probably underlay the microphthalmia in the proband. Above finding has facilitated prenatal diagnosis for this pedigree.

[Analysis of LRP5 gene variants in a Chinese pedigree affected with Osteoporosis-pseudoglioma syndrome].

OBJECTIVE: To explore the genetic basis for a Chinese pedigree with two individuals suffering from congenital blindness. METHODS: Clinical data and peripheral blood samples of the pedigree were collected. Whole exome sequencing was carried out. Suspected variants were verified by Sanger sequencing. Pathogenicity of candidate variants was validated through searching of PubMed and related databases, and analyzed with bioinformatics software. RESULTS: Both patients had congenital blindness and a history of multiple fractures. Other features have included microphthalmia and cornea opacity. One patient had normal intelligence, whilst the other had a language deficit. Both patients were found to harbor compound heterozygous variants of the LRP5 gene, namely c.1007_1015delGTAAGGCAG (p.C336X), c.4400G>A (p.R1467Q) and c.4600C>T (p.R1534X). The first one was derived from their mother, whilst the latter two were derived from their father. None of the three variants was detected in their elder sister. CONCLUSION: The compound heterozygous variants of c.1007_1015delGTAAGGCAG (p.C336X) and c.4600C>T (p.R1534X) of the LRP5 gene probably underlay the pathogenesis of the Osteoporosis-pseudoglioma syndrome in this pedigree. The clinical significance of the c.4400G>A (p.R1467Q) variant has remained uncertain. Above finding has enriched the mutational spectrum of Osteoporosis-pseudoglioma syndrome.

Molecular study and genotype-phenotype in Chinese female patients with 46, XY disorders of sex development.

OBJECTIVE: The rare condition 46, XY disorders of sex development (DSDs) is characterized by the female phenotype and male karyotype. We aimed to describe the genetic basis of 46, XY DSDs in nine patients and the genotype-phenotype relationships of the genes involved. METHODS: Targeted next-generation sequencing (NGS) was used to analyze the underlying hereditary etiology in nine female patients with 46, XY DSDs. In silico analyses were used to predict the effects of novel variants on the protein function of the identified genes. RESULTS: Primary amenorrhea with the absence of puberty, inguinal hernia, and clitoridauxe were common complaints. All enrolled patients had a differential etiology by genetic testing, and five novel genetic variants involved in four genes (SRY, AR, NR5A1, and LHCGR) were identified. A novel nonsense variant of SRY c.51C > G was found in XY patients without testicles. Two novel heterozygous variants, i.e. c.265A > T (Ile89Leu) and c.422T > C (Val141Ala), of the LHCGR gene were found in male pseudo-hermaphroditism. CONCLUSIONS: We expanded the genetic mutation spectrum and described in detail the genotype-phenotype relationships of 46, XY DSDs. DNA sequencing for SRY should be a priority in female patients with 46, XY DSDs. NGS is useful for clarifying genetic pathogenesis and could provide a basis for clinical diagnosis and treatments of patients with 46, XY DSDs.

[Identification of a fetus with complex chromosomal structural aberration by next-generation sequencing and karyotype analysis].

OBJECTIVE: To perform prenatal diagnosis for a woman carrying a balanced translocation. METHODS: Clinical phenotype of the woman and her first child was analyzed. Peripheral blood sample of the woman and amniotic fluid sample from two subsequent pregnancies were subjected to chromosomal karyotyping and copy number variation analysis through next-generation sequencing (NGS). RESULTS: The karyotypes of the woman and her first child were determined as 46,XX,t(5;6)(p15:p23) and 46,XX,?der(5),t(5;6)(p15.32;p22.3), respectively. The karyotype of the amniocyte from her second pregnancy was 46,XN,t(5;6)(p15:p23). No pathogenic copy number variation was detected. The karyotype of her third pregnancy was 46,XN,?der(5),t(5;6)(p15.32;p22. 3), in addition with a 6.04 Mb deletion at 5p15.33p15.32 (20 000 - 6 060 000) and a 18.50 Mb duplication at 6p25.3p22.3 (160 000 - 18 660 000). CONCLUSION: Combined karyotyping analysis and NGS has enabled detection of fetal copy number variations for a woman carrying a balanced chromosomal translocation.

[Phenotype and genetic variant analysis of seven pedigrees affected with blepharophimosis syndrome].

OBJECTIVE: To analyze the clinical manifestations and gene variants of patients with blepharophimosis, ptosis and epicanthus inversus syndrome (BPES). METHODS: Clinical data of 7 pedigrees affected with BPES were collected, and genomic DNA was extracted from peripheral blood samples of the probands and their relatives. All exons of the FOXL2 gene were subjected to Sanger sequencing. Those with negative findings were further screened by targeted capture and next generation sequencing (NGS) and microarray analysis. Pathogenicity of candidate variants were predicted by search of PubMed and related databases, and the impact of the variants was interpreted by protein prediction software. Diagnosis was confirmed by clinical phenotype, medical history and mutation analysis. RESULTS: A pathogenic variant was identified in six of the 7 pedigrees, which included four known pathogenic variants and one novel FOXL2 c.299dupA variant. A heterozygous 3q22.3q23 deletion, which encompassed the FOXL2 gene, was identified in another pedigree.As predicted, the c.299dupA frameshift mutation of FOXL2 gene can lead to the premature termination of protein translation, which is pathogenic. CONCLUSION: A novel and 5 known pathogenic variants have been identified in six pedigrees affected with BPES by the combined Sanger sequencing, target capture NGS and microarray analysis. Above findings have enabled genetic counseling and prenatal diagnosis for these pedigrees.

[Genetic testing and prenatal diagnosis for two families affected with Joubert syndrome].

OBJECTIVE: To identify pathogenic variants in two families with patients suspected for Joubert syndrome(UBST) by cerebellar vermis hypoplasia. METHODS: Clinical data and peripheral venous blood and skin tissue samples were collected for the extraction of genomic DNA. Potential variants were screened by using targeted capture and next generation sequencing. Suspected variants were validated by PCR and Sanger sequencing. The frequency of the variants in the population was calculated. Pathogenicity of the variants was predicted by following the guidelines of the American College of Medical Genetics and Genomics (ACMG). Prenatal diagnosis was provided to these families upon subsequent pregnancy. RESULTS: The proband of family 1 was found to harbor homozygous c.2072delT (p.F691S*fs19) frameshift variant of the AHI1 gene, which may cause premature termination of translation of the Abelson helper integration site 1 after the 691st amino acid. The proband of family 2 was found to harbor compound heterozygous variants of the CPLANE1 gene, namely c.7243dupA (p.T2415Nfs*7) and c.8001delG (p.K2667Nfs*31), which can respectively lead to premature termination of translation of ciliogenesis and planar polarity effector 1 after the 2145th and 2667th amino acids. All of the three variants were previously unreported, and were predicted to be pathogenic by bioinformatic analysis. CONCLUSION: The AHI1 c.2072delT and CPLANE1 c.7243dupA and c.8001delG variants probably underlay JBTS3 in family 1 and JBTS17 in family 2, respectively. Based on above results, prenatal diagnosis may be offered to the affected families upon their subsequent pregnancies.

[Clinical and genetic analysis of an infant with Lowe syndrome caused by exonic duplication of OCRL gene].

OBJECTIVE: To explore the genetic basis of an infant featuring congenital cataract, developmental delay and proteinuria. METHODS: Clinical data and peripheral blood samples of the family were collected. Potential variants were screened by using targeted capture and high-throughput sequencing on a NextSeq 500 platform. Suspected variant was verified by quantitative PCR. Pathogenicity of the candidate variant was predicted based on clinical presentation and laboratory tests. RESULTS: The infant's phenotypes included brain development retardation and proteinuria. Cranial MRI indicated widening of cerebral fissure, bilateral frontal and temporal subarachnoid cavities, and dysplasia of white matter myelination in posterior angular of ventricle. A novel duplication of exons 5 to 16 of the OCRL gene was found in the patient. His mother has carried the same duplication variant. CONCLUSION: The duplication variant of the OCRL gene probably underlies the oculo-cerebro-renal syndrome in the infant. Due to the heterogeneity of its clinical manifestation, pertinent genetic detection is essential for acurrate diagnosis of patients who have the related phenotypes.

[Clinical characteristics and variant analysis of five pedigrees with hereditary spastic paraplegia].

OBJECTIVE: To explore the clinical and genetic characteristics of five pedigrees affected with hereditary spastic paraplegia(HSP). METHODS: Clinical data of the five pedigrees was collected, and high-throughput sequencing was carried out to detect potential variants. Sanger sequencing were used to verify the results. RESULTS: The probands of pedigree 1 and 2 were found to harbor heterozygous SPAST gene variants, namely c.1196C>T and c.1523T>A. The proband of pedigree 3 harbored compound heterozygous variants of FA2H gene (c.61G>C and c.688G>A). Proband from pedigree 4 harbored compound heterozygous variants of SPG11 gene (c.6812+4_6812+7delAGTA and c.915delT). The proband of pedigree 5 harbored compound heterozygous variants of SPG7 gene (c.1703_1704delAG and c.1937-1G>C). Based on the American College of Medical Genetics and Genomics(ACMG) guidelines, all variants were predicted to be likely pathogenic. Among these, SPAST gene c.1523T>A, FA2H gene c.61.G>C, SPG11 gene splicing region c.6812+4_6812+7delAGTA, c.915delT, SPG7 gene c.1703_1704delAG and splicing region c.1937-1G>C variants were unreported previously. CONCLUSION: The probands of pedigrees 1 and 2 were diagnosed with autosomal dominant hereditary spastic paraplegia type 4, for which pedigree 2 showed incompletely penetrance. Pedigrees 3, 4, and 5 were diagnosed with autosomal recessive hereditary spastic paraplegia type 35, 11 and 7, respectively. Above result provided a reference for clinical diagnosis and genetic counseling for the affected pedigrees.

[Analysis of phenotype and CYP4V2 gene variants in two pedigrees affected with Bietti crystalline corneoretinal dystrophy].

OBJECTIVE: The CYP4V2 gene of two pedigrees affected with Bietti crystalline corneoretinal dystrophy was analyzed to indentify the cause of the disease and provide a basis for clinical diagnosis. METHODS: The probands were subjected to next generation sequencing (NGS). Suspected variants were verified by Sanger sequencing. Pathogenicity of the variants were searched through relevant databases and PubMed by following the ACMG guidelines. RESULTS: A homozygous variant in the CYP4V2 gene c. (802-8) _810delTCATACAGGTCATCGCTinsGC was detected in proband from pedigree 1, parents did not detect; CYP4V2 genes c. (802-8)_810delTCATACAGGTCATCGCTinsGC and c. 958 C>T (p.Arg320X) compound heterozygous variants existed in the proband of pedigree 2,both parents were variant carriers. The results of Sanger sequencing showed that the variant of CYP4V2 gene in the two families was consistent with the NGS sequencing. The c. (802-8)_810delTCATACAGGTCATCGCTinsGC of CYP4V2 gene was splicing variant, and both splicing variant and nonsense variant could produce truncated nonfunctional protein products. Based on standards and guidelines by American College of Medical Genetics and Genomics, the CYP4V2 genes c. (802-8)_810del TCATACAGGTCATCGCTinsGC and c. 958 C>T (p.Arg320X) were predicted to be pathogenic variants (PVS1+PS1+PM2+PM3). CONCLUSION: The homozygous variant c. (802-8) _810delTCATACAGGTCATCGCTinsGC and the complex heterozygous variants c. (802-8) _810delTCATACAGGTCATCGCTinsGC and c.958C>T (p.Arg320X) in CYP4V2 gene are the cause of the disease in the probands of two pedigrees , respectively.

[Identification and prenatal diagnosis of a novel NIPBL mutation underlying Cornelia De Lange syndrome].

OBJECTIVE: To explore the genetic basis for an infant featuring developmental delay, hand deformity and hypertonia of extremities. METHODS: Clinical data and peripheral blood samples of the proband and her parents were collected. Following DNA extraction, potential mutations were screened on an Ion PGM platform using a gene panel. Suspected mutation was verified by PCR and Sanger sequencing. RESULTS: A novel heterozygous nonsense mutation, c.2521C>T(p.R841X), was identified in the NIPBL gene. The mutation may cause premature termination of translation of the adhesion protein loading factor at 841st amino acids. The same mutation was not found in her parents and 931 healthy controls, and was absent from public databases including ExAC and 1000G. Bioinformatic analysis suggested the mutation to be disease causing. CONCLUSION: The c.2521C>T (p.R841X) mutation of the NIPBL gene probably underlies the Cornelia De Lange syndrome in the infant. Prenatal diagnosis may be provided to this family upon their subsequent pregnancy.

[Diagnosis of a case with mental retardation due to novel compound heterozygous variants of TRAPPC9 gene].

OBJECTIVE: To explore the genetic basis for a boy with mental retardation. METHODS: Clinical data and peripheral blood samples of the family were collected. Potential variants were screened by using a panel for genes associated with intellectual impairment. Suspected variants were verified by PCR and Sanger sequencing. RESULTS: The child presented with mental retardation, language delay and poor self-care. Imaging analysis showed widening of brain fissures and subarachnoid space, and dysplasia of corpus callosum. Three novel heterozygous variants, namely c.1705T to C (p.S569P), c.1708dupC (p.R570Pfs*80) and c.2273delA (p.N758Tfs*22), were identified in the TRAPPC9 gene. The mother of the proband has carried the c.1708dupC (p.R570Pfs*80) and c.1705T to C (p.S569P) variants, while his father has carried the c.2273delA (p.N758Tfs*22) variant. CONCLUSION: The compound heterozygous variants of the TRAPPC9 gene probably underlie the disease in this family. Considering the clinical and genetic heterogeneity of mental retardation, genetic testing is essential for attaining diagnosis for patients with the relevant phenotype.

[X-linked mental retardation combined with autism caused by a novel hemizygous mutation of GRIA3 gene].

OBJECTIVE: To explore the genetic basis for a family affected with mental retardation combined with autism. METHODS: For the family featuring X-linked recessive inheritance of mental retardation combined with autism, clinical data and peripheral blood samples were collected. Potential mutations of genes associated with intellectual impairment were sequenced with an Ion PGM platform. Suspected mutations were verified with a PCR-Sanger sequencing method. RESULTS: The patient with mental retardation had mild abnormal electroencephalograph(EEG), while brain MRI and CT scans showed no obvious abnormality. Two ABC (autism behavior checklist) testing scores were 73 and 66 when he was 7- and 13-year-old, respectively. A novel hemizygous mutation, c.64C>T (p.L22F), was detected in the GRIA3 gene in the patient, for which his mother was a heterozygous carrier. The mutation site was predicted to be possibly damaging and disease causing by PolyPhen_2 and MutationTaster. CONCLUSION: The novel hemizygous c.64C>T (p.L22F) mutation of the GRIA3 gene probably underlies the phenotypes of mental retardation combined with autism in this family. Considering the variable clinical manifestation of mental retardation and genetic heterogeneity of autism, genetic testing is essential for making the correct diagnosis.

[Identification of a novel RHO mutation in a pedigree affected with retinitis pigmentosa].

OBJECTIVE: To identify the pathogenic mutation underlying retinitis pigmentosa in a large pedigree. METHODS: The pedigree has included three generations showing an autosomal dominant transmission of retinitis pigmentosa. Potential mutations were screened using a retinitis pigmentosa gene panel and an Ion PGM platform. Suspected mutation was verified by Sanger sequencing. RESULTS: A novel heterozygous missense mutation, c.251T>C(p.Leu84Pro), was identified in the RHO gene. The mutation has co-segregated with the retinitis pigmentosa phenotype among all family members and was not found in public databases ExAC, 1000G and dbSNP or 831 healthy controls. The mutation was predicted to be damaging by three major protein-predicting software. CONCLUSION: The c.251T>C (p.Leu84Pro) mutation of the RHO gene is a novel pathogenic mutation underlying the retinitis pigmentosa phenotype in this pedigree. Above findings have enabled prenatal diagnosis for the pedigree.

[Analysis of a family with recurrent fetal copy number variations in 1p31.1].

OBJECTIVE: To analyze a family with recurrent fetal copy number variations (microdeletion and microduplication, respectively) of 1p31.1 using single nucleotide polymorphism-based array (SNP-array) and G banding chromosomal karyotyping. METHODS: Amniocentesis and chorionic villus sampling were performed for a woman during the two pregnancies. Whole genome SNP-array was used to detect genomic imbalance of the fetus. The couple was also subjected to G-banding chromosomal analysis and SNP-array analysis. RESULTS: SNP-array showed a 1p31.1 (70 164 686-83 474 843) ×1 and a 1p31.1 (70 164 686-83 479 747) ×3 in the fetuses during the two pregnancies, respectively. SNP array results of the couple appeared to be normal. The mother of the fetuses had a 46,XX,inv(1)(p31.1p32.1) karyotype. CONCLUSION: The paracentric inversion in chromosome 1 in the gravida probably underlies the recurrent 1p31.1 copy number variations in the fetuses. SNP-array combined with G banding chromosomal analysis are suitable for prenatal diagnosis for recurrent microdeletion and microduplication in the same chromosomal region, and can provide detailed information for genetic counseling.

[Application of Karyomapping for the prenatal diagnosis of five families affected with facioscapulohumerial muscular dystrophy type 1].

OBJECTIVE: To assess the value of Karyomapping for the prenatal diagnosis of facioscapulohumerial muscular dystrophy type 1 (FSHD1). METHODS: Peripheral blood and chorionic villi samples were collected from five families affected with FSHD1. Linkage-based diagnosis was carried out by using the Karyomapping method. Diagnosis for two fetal samples was carried out with the next-generation optical mapping system. RESULTS: The results of Karyomapping showed that three fetuses inherited the risky 4q35 region of the proband and two fetuses did not. The fetuses of families 1 and 2 received further diagnosis by the next-generation optical mapping system, and the results were consistent with those of Karyomapping. CONCLUSION: Karyomapping has enabled prenatal diagnosis for the five families affected with FSHD1. The method was faster and simpler compared with conventional strategies, though its feasibility still needs further validation. Since there were no SNP loci designed on the Karyomap chip for the DUX4 gene and its 3' flanking regions, misjudgment due to chromosomal recombination could not be completely eliminated. The accuracy of this method still needs further validation.

[Analysis of genetic difference between mild cognitive impairment and Alzheimer's disease through genome-wide association study].

OBJECTIVE: To explore the genetic difference between mild cognitive impairment (MCI) and Alzheimer's disease (AD) through association analysis of whole genome sequencing data. METHODS: Sequence data of 168 AD patients, 380 MCI patients and 261 elderly controls from the Alzheimer's Disease Neuroimaging Initiative (ADNI) project was collected. The genotype and phenotype association was analyzed through genome wide association study (GWAS). RESULTS: Sixteen single nucleotide polymorphisms (SNPs) were found to be associated with AD, and most of them were located on chromosome 19. This was consistent with the results of previous studies. Ten SNP loci were associated with MCI, and most of them were located on chromosome 9. The biological pathways associated with the SNP sets were calculated with a Plink Sets-based algorithm, and the results showed that the SNP loci sets associated with MCI and AD belonged to different biological pathways. CONCLUSION: The strictly adjusted result indicated that the SNP loci significantly associated with MCI and AD are different, and the nominal significant associated SNP loci showed that steady MCI and AD shared just a limited number of loci. This indicated that MCI and AD are different diseases bearing distinct genetic risks.

Distinctive RNA expression profiles in blood associated with Alzheimer disease after accounting for white matter hyperintensities.

BACKGROUND: Defining the RNA transcriptome in Alzheimer Disease (AD) will help understand the disease mechanisms and provide biomarkers. Though the AD blood transcriptome has been studied, effects of white matter hyperintensities (WMH) were not considered. This study investigated the AD blood transcriptome and accounted for WMH. METHODS: RNA from whole blood was processed on whole-genome microarrays. RESULTS: A total of 293 probe sets were differentially expressed in AD versus controls, 5 of which were significant for WMH status. The 288 AD-specific probe sets classified subjects with 87.5% sensitivity and 90.5% specificity. They represented 188 genes of which 29 have been reported in prior AD blood and 89 in AD brain studies. Regulated blood genes included MMP9, MME (Neprilysin), TGFß1, CA4, OCLN, ATM, TGM3, IGFR2, NOV, RNF213, BMX, LRRN1, CAMK2G, INSR, CTSD, SORCS1, SORL1, and TANC2. CONCLUSIONS: RNA expression is altered in AD blood irrespective of WMH status. Some genes are shared with AD brain.