Genetic testing for cerebral cavernous malformations

Abstract Cavernous cerebral malformations (CCM) are vascular malformations of the brain and spinal cord. CCM affect up to 0.5% of the general population, predisposing to headaches, seizures, cerebral hemorrhage and focal neurological deficit. CCM may be familial or sporadic. Familial forms have autosomal dominant inheritance. This Utility Gene Test was prepared on the basis of an analysis of the literature and existing diagnostic protocols. It is useful for confirming diagnosis, as well as for differential diagnosis, couple risk assessment and access to clinical trials

VHL Frameshift Mutation as Target of Nonsense-Mediated mRNA Decay in Drosophila melanogaster and Human HEK293 Cell Line

There are many well-studied examples of human phenotypes resulting from nonsense or frameshift mutations that are modulated by Nonsense-Mediated mRNA Decay (NMD), a process that typically degrades transcripts containing premature termination codons (PTCs) in order to prevent translation of unnecessary or aberrant transcripts. Different types of germline mutations in the VHL gene cause the von Hippel-Lindau disease, a dominantly inherited familial cancer syndrome with a marked phenotypic variability and age-dependent penetrance. By generating the Drosophila UAS:Upf1D45B line we showed the possible involvement of NMD mechanism in the modulation of the c.172delG frameshift mutation located in the exon 1 of Vhl gene. Further, by Quantitative Real-time PCR (QPCR) we demonstrated that the corresponding c.163delG human mutation is targeted by NMD in human HEK 293 cells. The UAS:Upf1D45B line represents a useful system to identify novel substrates of NMD pathway in Drosophila melanogaster. Finally, we suggest the possible role of NMD on the regulation of VHL mutations

Small Deletion at the 7q21.2 Locus in a CCM Family Detected by Real-Time Quantitative PCR

Cerebral cavernous malformations (CCMs) represent a common autosomal dominant disorder that predisposes patients to haemorrhagic strokes and focal neurological signs. About 56% of the hereditary forms of CCMs have been so far associated with mutations in the KRIT1 (Krev Interaction Trapped 1) gene, located at 7q21.2 (CCM1 locus). We described the complete loss of 7q21.2 locus encompassing the KRIT1 gene and 4 flanking genes in a CCM family by using a dense set of 12 microsatellite markers. The complete loss of the maternal copy of KRIT1 gene region was confirmed by Real-Time Quantitative Polymerase Chain Reaction (RT-QPCR) and the same approach was used for expression analysis. Additional RT-QPCR analysis showed the extension of the deletion, for a total of 700 kb, to the adjacent downstream and upstream-located genes, MTERF, AKAP9, CYP51A1, as well as a partial loss of the ANKIB1 gene. Here we report the molecular characterization of an interstitial small genomic deletion of the 7q21.2 region in a CCMs affected family, encompassing the KRIT1 gene. Our findings confirm the loss of function mechanism for the already known CCM1 locus, without any evident involvement of the other deleted genes. Moreover, our investigations highlight the usefulness of the RT-QPCR to the molecular characterization of the breakpoints genomic deletions and to the identification of internal deleted genes involved in the human genetic diseases

Candidate gene study of HOXB1 in autism spectrum disorder

<p>Abstract</p> <p>Background</p> <p><it>HOXB1 </it>plays a major role in brainstem morphogenesis and could partly determine the cranial circumference in conjunction with <it>HOXA1</it>. In our sample, <it>HOXA1 </it>alleles significantly influence head growth rates both in autistic patients and in population controls. An initial report, suggesting that <it>HOXB1 </it>could confer autism vulnerability in interaction with <it>HOXA1</it>, was not confirmed by five small association studies.</p> <p>Methods</p> <p>Our sample includes 269 autistic individuals, belonging to 219 simplex and 28 multiplex families. A mutational analysis of the two exons and flanking intronic sequences of the <it>HOXB1 </it>gene was carried out in 84 autistic patients by denaturing high performance liquid chromatography, followed by DNA sequencing. Identified rare variants were then searched by a restriction analysis in 236 autistic patients and 325-345 controls. Case-control and family-based association studies were performed on two common variants in 169 Italian patients versus 184 Italian controls and in 247 trios.</p> <p>Results</p> <p>We identified three common polymorphisms, rs72338773 [c.82insACAGCGCCC (INS/nINS)], rs12939811 [c.309A>T (Q103H)], and rs7207109 [c.450G>A (A150A)] and three rare variants, namely IVS1+63G>A, rs35115415 [c.702G>A (V234V)] and c.872_873delinsAA (S291N). SNPs rs72338773 and rs12939811 were not associated with autism, using either a case-control (alleles, exact <it>P </it>= 0.13) or a family-based design [transmission/disequilibrium test (TDT)χ²= 1.774, <it>P </it>= 0.183]. The rare variants, all inherited from one of the parents, were present in two Italian and in two Caucasian-American families. Autistic probands in two families surprisingly inherited a distinct rare variant from each parent. The IVS1+63A allele was present in 3/690 control chromosomes, whereas rare alleles at rs35115415 and c.872_873delinsAA (S291N) were not found in 662 and 650 control chromosomes, respectively. The INS-T309 allele influenced head size, but its effect appears more modest and shows no interaction with <it>HOXA1 </it>alleles. The INS-T309 allele is also associated with more severe stereotypic behaviours, according to ADI-R scores (<it>N </it>= 60 patients, <it>P </it>< 0.01).</p> <p>Conclusions</p> <p><it>HOXB1 </it>mutations do not represent a common cause of autism, nor do <it>HOXB1 </it>common variants play important roles in autism vulnerability. <it>HOXB1 </it>provides minor, albeit detectable contributions to head circumference in autistic patients, with <it>HOXA1 </it>displaying more prominent effects. <it>HOXB1 </it>variants may modulate the clinical phenotype, especially in the area of stereotypic behaviours.</p

Generation of induced pluripotent stem cell line CSSi008-A (4698) from a patient affected by advanced stage of Dentato-Rubral-Pallidoluysian atrophy (DRPLA)

Abstract Dentato-Rubral-pallidoluysian atrophy (DRPLA) is a rare autosomal, dominant, progressive neurodegenerative disease that causes involuntary movements, mental and emotional problems. DRPLA is caused by a mutation in the ATN1 gene that encodes for an abnormal polyglutamine stretch in the atrophin-1 protein. DRPLA is most common in the Japanese population, where it has an estimated incidence of 2 to 7 per million people. This condition has also been seen in families from North America and Europe. We obtained a reprogrammed iPSC line from a Caucasian patient with a juvenile onset of the disease, carrying 64 CAG repeat expansion in the ATN1 gene

Supratentorial cerebral cavernous malformations: clinical, surgical, and genetic involvement

Object Although there is general agreement on the methods of treatment for symptomatic supratentorial cerebral cavernous malformations (CMs) located in noneloquent areas, some controversy exists regarding the management of cerebral CMs that are asymptomatic and/or located in eloquent or deep areas. Moreover, recent advances in genetic findings could influence both standard clinical management and the follow-up strategy in affected individuals. Thus, the objective of this study was to develop, based on the authors' experience and a literature review, a management algorithm to deal with supratentorial cerebral CMs. Methods The authors retrospectively reviewed the clinical data related to 118 patients who underwent surgery for symptomatic supratentorial cerebral CMs at their institution. Twenty-eight of 118 patients harbored multiple lesions, and nine of these 28 patients had a clinically positive familial history. Genetic investigations were performed in 89 patients (75%). Conclusions Surgery for supratentorial cerebral CMs in noneloquent locations is safe and curative. In cerebral CMs located in deep and eloquent areas and with symptoms including progressive neurological deficits, evidence of hemorrhage, and uncontrolled seizures, surgical treatment according to an integrated plan based on frameless stereotactic guidance and functional magnetic resonance imaging is recommended and results in acceptably low morbidity. The data support the need for long-term imaging follow up in all patients, careful preoperative vascular studies to detect associated venous anomalies, and the importance of genetic mutational analysis. The DNA screening protocol will change the care of family members of patients with familial forms of cerebral CMs, because affected asymptomatic family members may benefit by early detection of lesions. At the same time, the exclusion of family members who are not carriers of the mutation as members of the population at risk reduces the economic and psychological burden of clinical and instrumental monitoring

Leber's hereditary optic neuropathy (LHON) in an Apulian cohort of subjects

Leber's hereditary optic neuropathy (LHON) is a maternally inherited disorder that causes severe loss of sight in young adults, and is typically associated to mitochondrial DNA (mtDNA) mutations. Heteroplasmy of primary LHON mutations, presence of 'ancillary' mtDNA mutations, and mtDNA copy number are probably correlated with the penetrance and the severity of the disease. In this study, we performed a mutational screening in an Apulian cohort of LHON patients and we found that 41 out of 54 subjects harbored the m.11778G>A mutation, and 13 harbored the m.3460G>A mutation. Whole mtDNA sequencing was performed in three affected subjects belonging to three unrelated m.11778G>A pedigrees to evaluate the putative synergistic role of additional mtDNA mutations in determining the phenotype. Our study suggests to include haplogroup T as a possible genetic background influencing LHON penetrance and to consider the increase of mtDNA copy number as a protective factor from vision loss regardless the hetero/homoplasmic status of LHON primary mutations

Osteoporosis-pseudoglioma syndrome: Report of two cases and a manifesting carrier

BACKGROUND: Osteoporosis-pseudoglioma syndrome is a very rare disease mainly characterized by severe eye abnormalities and osteoporosis but also causing a broader range of clinical features. The syndrome is associated with homozygous or compound heterozygous variations in the LRP5 gene. In this report, we describe two children with a severe early-onset form of familial exudative vitreoretinopathy associated with skeletal abnormalities. MATERIALS AND METHODS: Two probands (4 and 7 years of age respectively) and their parents were assessed by genetic analysis and comprehensive ophthalmic examination. RESULTS: In both probands, the diagnosis of osteoporosis-pseudoglioma syndrome was confirmed by detection of three new pathogenic LRP5 variants: p.(Asp379Asn), found in the homozygous state in one proband, and p.(Asp203Ala) in the compound heterozygous state with p.(Cys612Valfs*25) in the other. The clinical and genetic study was extended to their parents, confirming that heterozygous carriers may also have incomplete clinical manifestation of this syndrome. CONCLUSIONS: To our knowledge, these are the first two cases of the syndrome described in Italy. Genetic testing proved to be fundamental for definition of the syndrome and confirms the importance of early detection of LRP5 variants for management of systemic features of the disease in patients and carrier relatives

Mitochondrial DNA copy number differentiates the Leber's hereditary optic neuropathy affected individuals from the unaffected mutation carriers

[No abstract available