Identification of a novel truncating mutation in PALB2 gene by a multigene sequencing panel for mutational screening of breast cancer risk-associated and related genes.

BACKGROUND: Breast cancer (BC) is the most common neoplasm in women, with 5%-10% patients showing a familial predisposition, where germline mutations in BRCA1/BRCA2 genes are found in -20% of cases. Next-generation sequencing (NGS) is among the best available options for genetic screening, providing several benefits that include enhanced sensitivity and unbiased mutation detection. PALB2 (partner and localizer of BRCA2) is a cancer predisposing gene recently described that encodes a protein partner of BRCA2 involved in DNA double-strand break repair and cell cycle control. The DNA damage response represents a key cellular event, targeted by innovative anticancer therapies, including those based on poly (ADP-ribose) polymerase (PARP) inhibitors targeting PARP1 and PARP2 enzymes, activated by DNA damage and involved in single-strand break and base excision repair. METHODS: Genomic DNA was isolated from 34 patient samples and four BC cell lines, as controls, and 27 breast cancer predisposing genes belonging to the BRCA1/BRCA2 and PARP pathways were sequenced by NGS. RESULTS: The panel described here allowed identification of several sequence variations in most investigated genes, among which we found a novel truncating mutation in PALB2. CONCLUSIONS: The NGS-based strategy designed here for molecular analysis of a customized panel of BC predisposing and related genes was found to perform effectively, providing a comprehensive exploration of all genomic sequences of the investigated genes. It is thus useful for BC molecular diagnosis, in particular for familiar cases where alterations in routinely investigated genes, such as BRCAs, result to be absent.

Characterization of two de novoKCNT1 mutations in children with malignant migrating partial seizures in infancy.

The KCNT1 gene encodes for subunits contributing to the Na(+)-activated K(+) current (KNa), expressed in many cell types. Mutations in KCNT1 have been found in patients affected with a wide spectrum of early-onset epilepsies, including Malignant Migrating Partial Seizures in Infancy (MMPSI), a severe early-onset epileptic encephalopathy characterized by pharmacoresistant focal seizures migrating from one brain region or hemisphere to another and neurodevelopment arrest or regression, resulting in profound disability. In the present study we report identification by whole exome sequencing (WES) of two de novo, heterozygous KCNT1 mutations (G288S and, not previously reported, M516V) in two unrelated MMPSI probands. Functional studies in a heterologous expression system revealed that channels formed by mutant KCNT1 subunits carried larger currents when compared to wild-type KCNT1 channels, both as homo- and heteromers with these last. Both mutations induced a marked leftward shift in homomeric channel activation gating. Interestingly, the KCNT1 blockers quinidine (3-1000µM) and bepridil (0.03-10µM) inhibited both wild-type and mutant KCNT1 currents in a concentration-dependent manner, with mutant channels showing higher sensitivity to blockade. This latter result suggests two genotype-tailored pharmacological strategies to specifically counteract the dysfunction of KCNT1 activating mutations in MMPSI patients.

A case of restless leg syndrome in a family with LRRK2 gene mutation.

LRRK2 gene mutations (PARK8) are a common cause of genetic Parkinson disease (PD). G2019S, the most frequent mutation, is responsible for both familial and sporadic cases of PD. The clinical picture is usually indistinguishable from that observed in idiopathic PD; however, a wide range of clinical presentations and pathological findings has been described. Restless leg syndrome (RLS) is a disabling sleep-related sensorimotor disorder whose pathogenesis is likely related to dopaminergic dysfunction. We report a 77-year-old woman with RLS and familial history of parkinsonism. The father, one sister, two cousins and one uncle were affected by PD. The proband and her sister were analyzed for mutations in LRRK2 gene and resulted to carry one heterozygous G2019S mutation in LRRK2 gene. The association between RLS and LRRK2 gene mutation may be casual, but it can hypothesized that RLS is a possible phenotypic presentation in PARK8.

Epoetin alfa increases frataxin production in Friedreich's ataxia without affecting hematocrit.

Objective of the study was to test the efficacy, safety, and tolerability of two single doses of Epoetin alfa in patients with Friedreich's ataxia. Ten patients were treated subcutaneously with 600 IU/kg for the first dose, and 3 months later with 1200 IU/kg. Epoetin alfa had no acute effect on frataxin, whereas a delayed and sustained increase in frataxin was evident at 3 months after the first dose (+35%; P < 0.05), and up to 6 months after the second dose (+54%; P < 0.001). The treatment was well tolerated and did not affect hematocrit, cardiac function, and neurological scale. Single high dose of Epoetin alfa can produce a considerably larger and sustained effect when compared with low doses and repeated administration schemes previously adopted. In addition, no hemoglobin increase was observed, and none of our patients required phlebotomy, indicating lack of erythropoietic effect of single high dose of erythropoietin.

The LRRK2 R1441C mutation is more frequent than G2019S in Parkinson's disease patients from southern Italy.

BACKGROUND: Mutations in the leucine-rich repeat kinase 2 gene are the most frequent cause of familial and sporadic Parkinson's disease, and G2019S is the most common leucine-rich repeat kinase 2 mutation across several Mediterranean countries. METHODS: One hundred ninety-two patients with Parkinson's disease from Campania, a region in southern Italy, were screened for R1441C/H/G and G2019S by direct sequencing and SfcI digestion. RESULTS: Among 192 patients with Parkinson's disease (mean age±SD, 63.9±11.8 years; disease onset, 54.0±12.5 years; family history for Parkinson's disease or tremor, 45%), 8 carried a heterozygous R1441C mutation, whereas only 1 had the G2019S mutation. All R1441C patients originate from the province of Naples and share the same haplotype, suggesting a founder effect. CONCLUSIONS: G2019S is not ubiquitously the most common leucine-rich repeat kinase 2 mutation; in Campania R1441C is more frequent. Region-specific mutation prevalence data should be taken into account for a sensitive and cost-effective molecular diagnosis and counseling of patients with Parkinson's disease.

An Overview of Candidate Therapeutic Target Genes in Ovarian Cancer.

Ovarian cancer (OC) shows the highest mortality rate among gynecological malignancies and, because of the absence of specific symptoms, it is frequently diagnosed at an advanced stage, mainly due to the lack of specific and early biomarkers, such as those based on cancer molecular signature identification. Indeed, although significant progress has been made toward improving the clinical outcome of other cancers, rates of mortality for OC are essentially unchanged since 1980, suggesting the need of new approaches to identify and characterize the molecular mechanisms underlying pathogenesis and progression of these malignancies. In addition, due to the low response rate and the high frequency of resistance to current treatments, emerging therapeutic strategies against OC focus on targeting single factors and pathways specifically involved in tumor growth and metastasis. To date, loss-of-function screenings are extensively applied to identify key drug targets in cancer, seeking for more effective, disease-tailored treatments to overcome lack of response or resistance to current therapies. We review here the information relative to essential genes and functional pathways recently discovered in OC, often strictly interconnected with each other and representing promising biomarkers and molecular targets to treat these malignancies.

Genetic screening for the LRRK2 R1441C and G2019S mutations in Parkinsonian patients from Campania.

BACKGROUND: PARK8 is the most common known mendelian form of Parkinson's Disease (PD). It is due to mutations in the leucine-rich repeat kinase 2 (LRRK2) gene and G2019S is considered the most frequent mutation in the Caucasian population, in particular in the Southern Europe and Mediterranean countries. OBJECTIVE: We assessed the frequency of the G2019S and R1441C/H/G mutations in 513 (311 M and 202 F) unrelated PD patients from Campania, in Southern Italy. METHODS: Three hundreds and thirty-six patients presented a sporadic disease, and 177 had a familial history of PD or tremor. Three hundreds and eighty cases originated from the province of Naples. We compared our LRRK2 mutation carriers to idiopathic PD patients matched for recruiting center, gender, age and age at onset. RESULTS: Thirteen patients (8 M and 5 F) carried the R1441C mutation and 4 (3 M and 1 F) the G2019S mutation, all in heterozygous state. All carriers originated from the province of Naples. No carriers of the R1441H or R1441G mutations were found. The LRRK2 mutation carriers were clinically similar to idiopathic PD patients. The R1441C and G2019S mutations are not rare causes of PD in Campania, especially in the province of Naples and among the familial cases, where the overall mutation prevalence is 6.8%. CONCLUSIONS: The R1441C prevalence was higher than that of G2019S (2.5% vs 0.8%), underlining the importance of the geographical differencies in LRRK2 mutation frequency for molecular screening and genetic counseling of PD patients.