De novo inverted interstitial (“mirror”) duplication of chromosome 8(q13→q24.1) in a liveborn male

We report on a newborn boy with a de novo inverted interstitial duplication of chromosome 8(q13→q24.1). This form of cytogenetic abnormality, in which a mirror image interstitial duplication has occurred, is exceedingly rare. Review of the literature and mechanisms to explain the origin of this type of chromosome aberration are presented. A review of the findings from individuals with partial dup(8q) demonstrate remarkable similarity to the infant we describe.     

Multiple candidate gene analysis identifies alpha-synuclein as a susceptibility gene for sporadic Parkinson's disease

Parkinson's disease (PD), one of the most common human neurodegenerative diseases, is characterized by the loss of dopaminergic neurons in the substantia nigra of the midbrain. PD is a complex disorder with multiple genetic and environmental factors influencing disease risk. To identify susceptible genes for sporadic PD, we performed case-control association studies of 268 single nucleotide polymorphisms (SNPs) in 121 candidate genes. In two independent case-control populations, we found that a SNP in alpha-synuclein (SNCA), rs7684318, showed the strongest association with PD (P=5.0 x 10(-10)). Linkage disequilibrium (LD) analysis using 29 SNPs in a region around rs7684318 revealed that the entire SNCA gene lies within a single LD block (D'>0.9) spanning approximately 120 kb. A tight LD group (r2>0.85) of six SNPs, including rs7684318, associated most strongly with PD (P=2.0 x 10(-9)-1.7 x 10(-11)). Haplotype association analysis did not show lower P-values than any single SNP within this group. SNCA is a major component of Lewy bodies, the pathological hallmark of PD. Aggregation of SNCA is thought to play a crucial role in PD. SNCA expression levels tended to be positively correlated with the number of the associated allele in autopsied frontal cortices. These findings establish SNCA as a definite susceptibility gene for sporadic PD.     

Vitamin D receptor gene as a candidate gene for Parkinson disease

Vitamin D and vitamin D receptor (VDR) have been postulated as environmental and genetic factors in neurodegeneration disorders including multiple sclerosis (MS), Alzheimer disease (AD), and recently Parkinson disease (PD). Given the sparse data on PD, we conducted a two-stage study to evaluate the genetic effects of VDR in PD. In the discovery stage, 30 tagSNPs in VDR were tested for association with risk as a discrete trait and age-at-onset (AAO) as a quantitative trait in 770 Caucasian PD families. In the validation stage, 18 VDR SNPs were tested in an independent Caucasian cohort (267 cases and 267 controls) constructed from a genome-wide association study (GWAS). In the discovery dataset, SNPs in the 5' end of VDR were associated with both risk and AAO with more significant evidence of association with AAO (P= 0.0008-0.02). These 5' SNPs were also associated with AD in another study. In the validation dataset, SNPs in the 3' end of VDR were associated with AAO (P= 0.003) but not risk. The 3' end SNP has been associated with both MS and AD in previous studies. Our findings suggest VDR as a potential susceptibility gene and support an essential role of vitamin D in PD.     

Trisomy 18 and a constitutional maternal translocation (2;18)

Parental chromosomes are usually not analyzed in cases of trisomy 18 because the extra 18 is assumed to have arisen through a meiotic nondisjunctional event. We report on a case of a trisomy 18 and a maternal translocation (2;18)(q34;q12). © 1992 Wiley-Liss, Inc.     

“C” Trigonocephaly syndrome: Report of a child with agenesis of the corpus callosum and tetralogy of Fallot,and review

We report on a new case of the Opitz “C” trigonocephaly syndrome. Our patient had agenesis of the corpus callosum, an anomaly seen only twice previously, and tetralogy of Fallot, described only once before. A review shows that a combination of conotruncal heart defects and midline brain anomalies characterizes patients with this entity. © 1995 Wiley-Liss, Inc.     

Cytogenetic and endocrine findings in a female with 45, X, t(Y;18) (p11;p11)

A 23-year-old phenotypic female with congenital heart disease, mental retardation and mild virilization was referred for evaluation of short stature and delayed sexual development. Endocrine studies revealed a markedly elevated serum testosterone, which was within the adult male range. At laparotomy, a small uterus, normal fallopian tubes and bilateral gonadal tumors, consisting of a left gonadoblastoma and right dysgerminoma were found. Trypsin G banding of peripheral blood revealed a 45, XO, 18p+ karyotype. Q banding demonstrated intense fluorescence of the distal portion of the extra material on chromosome 18, consistent with fluorescence of Y chromosomal heterochromatin. A combination of banding techniques enabled us to determine a 45, X, t(Y;18) (p11;p11) karyotype in peripheral blood. Cultures of gonadal tissue revealed 45, X, t(Y;18)/46, XY mosaicism.     

Three cell line mosaicism involving structural and numerical abnormalities of chromosome 18 in a 3.5‐Year‐old girl: 47,XX,+18/47,XX,+del(18)(q22)/46,XX

We report on a 3.5‐year‐old girl with a mosaic karyotype including full trisomy 18, normal cells and a majority of cells with partial trisomy involving an extra chromosome 18 deleted at band q22. She had cardiac and CNS anomalies, dysmorphic facial features failure to thrive and developmental delay. A gastrostomy tube was placed at 2 years of age. The combination of improved nutrition and optimal developmental therapy has led to her sitting supported, attempting to stand and enhancement of her cognitive and non‐verbal communication abilities. Molecular investigation of the patient and her parents using microsatellite analysis has led to the conclusion that, as expected, the additional copy of chromosome 18 constituting the full trisomic cell line is maternal meiosis I in origin. The data, however, indicate that in the trisomic cell line containing the deleted chromosome 18q, the structurally abnormal 18 was of paternal origin. We think this case is the first described with both structural and numerical trisomic mosaicism involving chromosome 18 in a liveborn infant. We propose a mechanism of origin and review the literature, comparing the clinical presentation of this case with individuals having full or partial trisomy 18. © 2001 Wiley‐Liss, Inc.     

Multiregional gene expression profiling identifies MRPS6 as a possible candidate gene for Parkinson's disease

Combining large-scale gene expression approaches and bioinformatics may provide insights into the molecular variability of biological processes underlying neurodegeneration. To identify novel candidate genes and mechanisms, we conducted a multiregional gene expression analysis in postmortem brain. Gene arrays were performed utilizing Affymetrix HG U133 Plus 2.0 gene chips. Brain specimens from 21 different brain regions were taken from Parkinson's disease (PD) (n = 22) and normal aged (n = 23) brain donors. The rationale for conducting a multiregional survey of gene expression changes was based on the assumption that if a gene is changed in more than one brain region, it may be a higher probability candidate gene compared to genes that are changed in a single region. Although no gene was significantly changed in all of the 21 brain regions surveyed, we identified 11 candidate genes whose pattern of expression was regulated in at least 18 out of 21 regions. The expression of a gene encoding the mitochondria ribosomal protein S6 (MRPS6) had the highest combined mean fold change and topped the list of regulated genes. The analysis revealed other genes related to apoptosis, cell signaling, and cell cycle that may be of importance to disease pathophysiology. High throughput gene expression is an emerging technology for molecular target discovery in neurological and psychiatric disorders. The top gene reported here is the nuclear encoded MRPS6, a building block of the human mitoribosome of the oxidative phosphorylation system (OXPHOS). Impairments in mitochondrial OXPHOS have been linked to the pathogenesis of PD.     

San Luis Valley Recombinant chromosome 8 and tetralogy of Fallot: A review of chromosome 8 anomalies and congenital heart disease

Tetralogy of Fallot, the most common cyanotic heart defect, has not been closely associated with a specific chromosome defect. The San Luis Valley Recombinant Chromosome 8 [SLV Rec(8)] syndrome is strongly associated with congenital heart disease, particularly tetralogy of Fallot. This article reviews SLV Rec(8) syndrome and other chromosome 8 aberrations to suggest locations for cardiogenic genes. SLV Rec(8) [rec(8), dup q,inv(8)(p23q22)] syndrome has been found in Hispanic families in the southwestern United States. Congenital heart disease is found in 93.3% of SLV Rec(8) individuals (n = 45), with tetralogy of Fallot constituting 40.5% of all lesions and conotruncal defects, 55.6%. These frequencies exceed the incidence of tetralogy of Fallot (10%) and conotruncal defects (20%) among all children with heart defects (P<0.003 for both). Review of patients with deletion 8p (n=13) showed heart defects in 84.6% with 27.3% being conotruncal defects. Among duplication 8q patient (n = 20), 45% had heart defects with conotruncal defects constituting 44%. Neither group differed significantly from expected in its incidence of conotruncal defects. Among patients with mosaic trisomy 8 (n = 47), 12 had heart abnormalities including one conotruncal defect. Among 3 patients with other rec(8) chromosomes, one had a ventricular septal defect. The cause of heart defects in SLV Rec(8) cannot be assigned to either the deletion of 8p or the duplication of 8q. The lack of an association between other chromosome 8 abnormalities and tetralogy of Fallot suggests that genes at the SLV Rec(8) breakpoints or an interaction between genes on both arms of chromosome 8 are important.     

Five generations of t(4;8)(q35;q13) leading to a case of partial 8q trisomy with consideration of potential pregnancy outcomes from translocation carriers

We describe a female infant with partial trisomy 8q who has rnicrophthalmia, a cleft palate, micrognathia and a heart defect. Her dysmorphogenetic features closely resemble the characteristic pattern seen in the 17 cases thus far reported in the literature. Her chromosomal defect was caused by an unbalanced translocation, inherited through her father, and found to have been transmitted through at least 5 generations. Recently developed models designed to predict the most probable mode of unbalanced segregation from the meiotic quadrivalent and the likelihood that a chromosomally unbalanced fetus will survive to term are applied to this family's translocation. Also, the frequencies of potential reproductive outcomes from carriers of this translocation generated from empiric data are considered as a requisite aid to genetic counseling.     

Rates and survival of individuals with trisomy 13 and 18 Data from a 10-year period in Denmark

Rates and survival figures for trisomy 13 and trisomy 18 have been calculated for Denmark (DK) based on a 10-year period (1977-86). The data have been ascertained through The Danish Central Cytogenetic Register, all cytogenetic laboratories in DK, paediatric departments throughout the country. The Medical Birth Register and The Register of Causes of Death in DK. Nineteen liveborn probands with trisomy 13 and 76 liveborn probands with trisomy 18 were found. No stillborn cases with trisomy 13 but 6 with trisomy 18 were found. By prenatal diagnosis 19 probands with trisomy 13 and 46 with trisomy 18 were found. Based on liveborn and stillborn probands, the prevalence at birth was 1 per 29,374 for trisomy 13 and 1 per 6806 for trisomy 18. The median survival for trisomy 13 was 2.5 days, while the same figure for trisomy 18 was 6.0 days. The rates calculated seem rather low compared to earlier studies.     

Vertebral hypersegmentation in a case of the VATER association

Associations are statistical clusterings of malformations not known to be polytopic field defects, sequences, or syndromes. The VATER association is a nonrandom association of malformations including vertebral, anal, cardiovascular, tracheoesophageal, genitourinary, and limb defects. The caudal “dysplasia” sequence of lumbosacral vertebral defects, genitourinary abnormalities, and imperforate anus overlaps the VATER association. The cloacal membrane agenesis sequence is a pattern of malformations resulting in the absence of anal, genital, and urinary orifices with associated malformations in surrounding structures. We report on a 37-week gestation liveborn male with oligohydramnios deformations, tetralogy of Fallot, “H-type” tracheoesophageal fistula, duodenal atresia, imperforate anus, urethral atresia, undescended testes, absent right kidney with a small dysplastic left kidney, a “cloacal-like” abnormality of the bladder and distal bowel, and thoracic and lumbar vertebral hypersegmentation. This patient has manifestations of the VATER association, the caudal dysplasia sequence, and the cloacal membrane agenesis sequence. We propose that some of his defects may represent a malformation sequence secondary to excessive embryonic flexion resulting from vertebral hypersegmentation.     

Structural and mutational analysis of the xeroderma pigmentosum group D (XPD) gene

Individuals affected by the autosomal recessive disease xerodermapigmentosum (XP) are acutely sensitive to sunlight and predisposedto skin cancer on exposed areas. Cells cultured from XP patientsare both UV sensitive and defective in the nucleotide excisionrepair of damaged DNA. These cellular phenotypes are amenableto experimental strategies employing complementation, an approachpreviously used to demonstrate the correction of XP-D phenotypesfollowing the introduction of the XPD (ERCC2) gene. In the presentstudy, we have characterized the genomic organization of theXPD (ERCC2) gene and found it to be comprised of 23 exons. Thesedata were helpful in evaluating the functional integrity ofalleles in two XP-D cell lines. In cell line GM436 a C     

Mutations of ZFPM2/FOG2 gene in sporadic cases of tetralogy of Fallot

Two out of 47 patients with sporadic tetralogy of Fallot (TOF), the most common cyanotic conotruncal heart defect (CTD), showed heterozygous missense mutations of the ZFPM2/FOG2 gene. Knockout mice carrying mutations in the ZFPM2/FOG2 gene have similarly been found to exhibit TOF. While both mutant ZFPM2/FOG2 proteins, E30G (c.88A>G) and S657G (c.1968A>G), retain the ability to bind the partner protein GATA4 and repress GATA4 mediated gene activation, the S657G, but not the E30G, mutation is subtly impaired in this function. ZFPM2/FOG2 gene mutations may contribute to some sporadic cases of TOF.     

Frontonasal malformation with tetralogy of Fallot associated with a submicroscopic deletion of 22q11

We report on a 14-month-old girl with bifid nasal tip and tetralogy of Fallot. Several similar patients have been described with CNS or eye abnormalities. Chromosome analysis with FISH, using Oncor DiGeorge probes, confirmed a submicroscopic deletion of 22q11. Many patients with Shprintzen (velo-cardio-facial) syndrome have a similar deletion with conotruncal cardiac defects and an abnormal nasal shape, suggesting that a gene in this area, possibly affecting neural crest cells, influences facial and other midline development. Am. J. Med. Genet. 69:287–289, 1997. © 1997 Wiley-Liss, Inc.     

Whole‐Genome Sequencing and Integrative Genomic Analysis Approach on Two 22q11.2 Deletion Syndrome Family Trios for Genotype to Phenotype Correlations

The 22q11.2 deletion syndrome (22q11DS) affects 1:4,000 live births and presents with highly variable phenotype expressivity. In this study, we developed an analytical approach utilizing whole‐genome sequencing (WGS) and integrative analysis to discover genetic modifiers. Our pipeline combined available tools in order to prioritize rare, predicted deleterious, coding and noncoding single‐nucleotide variants (SNVs), and insertion/deletions from WGS. We sequenced two unrelated probands with 22q11DS, with contrasting clinical findings, and their unaffected parents. Proband P1 had cognitive impairment, psychotic episodes, anxiety, and tetralogy of Fallot (TOF), whereas proband P2 had juvenile rheumatoid arthritis but no other major clinical findings. In P1, we identified common variants in COMT and PRODH on 22q11.2 as well as rare potentially deleterious DNA variants in other behavioral/neurocognitive genes. We also identified a de novo SNV in ADNP2 (NM_014913.3:c.2243G>C), encoding a neuroprotective protein that may be involved in behavioral disorders. In P2, we identified a novel nonsynonymous SNV in ZFPM2 (NM_012082.3:c.1576C>T), a known causative gene for TOF, which may act as a protective variant downstream of TBX1, haploinsufficiency of which is responsible for congenital heart disease in individuals with 22q11DS.