Characterization of novel progranulin gene variants in Italian patients with neurodegenerative diseases.

Loss-of-function mutations in the gene encoding for the protein progranulin (PGRN), GRN, are one of the major genetic abnormalities involved in frontotemporal lobar degeneration. However, genetic variations, mainly missense, in GRN have also been linked to other neurodegenerative diseases. We found 12 different pathogenic/likely pathogenic variants in 21 patients identified in a cohort of Italian patients affected by various neurodegenerative disorders. We detected the p.Thr272SerfsTer10 as the most frequent, followed by the c.1179+3A>G variant. We characterized the clinical phenotype of 12 patients from 3 pedigrees carrying the c.1179+3A>G variant, demonstrated the pathogenicity of this mutation, and detected other rarer variants causing haploinsufficiency (p.Met1?, c.709-2A>T, p.Gly79AspfsTer39). Finally, by applying bioinformatics, neuropathological, and biochemical studies, we characterized 6 missense/synonymous variants (p.Asp94His, p.Gly117Asp, p.Ala266Pro, p.Val279Val, p.Arg298His, p.Ala505Gly), including 4 previously unreported. The designation of variants is crucial for genetic counseling and the enrollment of patients in clinical studies.

Two novel PRNP truncating mutations broaden the spectrum of prion amyloidosis.

Truncating mutations in PRNP have been associated with heterogeneous phenotypes ranging from chronic diarrhea and neuropathy to dementia, either rapidly or slowly progressive. We identified novel PRNP stop-codon mutations (p.Y163X, p.Y169X) in two Italian kindreds. Disease typically presented in the third or fourth decade with progressive autonomic failure and diarrhea. Moreover, one proband (p.Y163X) developed late cognitive decline, whereas some of his relatives presented with isolated cognitive and psychiatric symptoms. Our results strengthen the link between PRNP truncating mutations and systemic abnormal PrP deposition and support a wider application of PRNP screening to include unsolved cases of familial autonomic neuropathy.

Identification of rare genetic variants in Italian patients with dementia by targeted gene sequencing.

Genetics is intricately involved in the etiology of neurodegenerative dementias. The incidence of monogenic dementia among all neurodegenerative forms is unknown due to the lack of systematic studies and of patient/clinician access to extensive diagnostic procedures. In this study, we conducted targeted sequencing in 246 clinically heterogeneous patients, mainly with early-onset and/or familial neurodegenerative dementia, using a custom-designed next-generation sequencing panel covering 27 genes known to harbor mutations that can cause different types of dementia, in addition to the detection of C9orf72 repeat expansions. Forty-nine patients (19.9%) carried known pathogenic or novel, likely pathogenic, variants, involving both common (presenilin 1, presenilin 2, C9orf72, and granulin) and rare (optineurin, serpin family I member 1 and protein kinase cyclic adenosine monophosphate (cAMP)-dependent type I regulatory subunit beta) dementia-associated genes. Our results support the use of an extended next-generation sequencing panels as a quick, accurate, and cost-effective method for diagnosis in clinical practice. This approach could have a significant impact on the proportion of tested patients, especially among those with an early disease onset.

The First Historically Reported Italian Family with FTD/ALS Teaches a Lesson on C9orf72 RE: Clinical Heterogeneity and Oligogenic Inheritance.

BACKGROUND: In 1969, Dazzi and Finizio reported the second observation of frontotemporal dementia (FTD) - amyotrophic lateral sclerosis (ALS) association in a large Italian kindred affected by an autosomal dominant form of ALS with high penetrance, frequent bulbar onset, and frequent cognitive decline. OBJECTIVE: To expand the original characterization of this family and report the link with the C9orf72 repeat expansion (RE). METHODS: We followed or reviewed the medical records of thirteen patients belonging to the original family and performed genetic analyses in four individuals. RESULTS: Eight patients presented with ALS, four with FTD, and one with schizophrenia. The C9orf72 RE was found in three patients but not in the healthy survivor. Additionally, we found a novel possible pathogenic variant in the ITM2B gene in one patient with a complex phenotype, associating movement disorders, psychiatric and cognitive features, deafness, and optic atrophy. The neuropathological examination of this patient did not show the classical features of ITM2B mutation related dementias suggesting that the putative pathogenic mechanism does not involve cellular mislocalization of the protein or the formation of amyloid plaques. CONCLUSION: We showed that the original Italian pedigree described with FTD/ALS carries the C9orf72 RE. Moreover, the finding of an additional mutation in another dementia causing gene in a patient with a more complex phenotype suggests a possible role of genetic modifiers in the disease. Together with other reports showing the coexistence of mutations in multiple ALS/FTD causative genes in the same family, our study supports an oligogenic etiology of ALS/FTD.

Multiple variants in families with amyotrophic lateral sclerosis and frontotemporal dementia related to C9orf72 repeat expansion: further observations on their oligogenic nature.

The C9orf72 repeat expansion (RE) is one of the most frequent causative mutations of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). However, it is still unclear how the C9orf72 RE can lead to a heterogeneous phenotype. Several reports have shown the coexistence of mutations in multiple ALS/FTD causative genes in the same family, suggesting an oligogenic etiology for ALS and FTD. Our aim was to investigate this phenomenon in an Italian group of ALS/FTD pedigrees carrying the C9orf72 RE. We included 11 subjects from 11 pedigrees with ALS/FTD and the C9orf72 RE. Mutation screening of FUS, SOD1 and TARDBP genes was performed by direct sequencing. A dementia-specific custom-designed targeted next-generation sequencing panel was used for screening dementia-associated genes mutations. We found genetic variants in additional ALS or dementia-related genes in four pedigrees, including the p.V47A variant in the TYROBP gene. As a group, double mutation carriers displayed a tendency toward a younger age at onset and a higher frequency of positive familiar history and of parkinsonism. Our observation supports the hypothesis that the co-presence of mutations in different genes may be relevant for the clinical expression of ALS/FTD and of their oligogenic nature.

A patient with PMP22-related hereditary neuropathy and DBH-gene-related dysautonomia.

Recurrent focal neuropathy with liability to pressure palsies is a relatively frequent autosomal-dominant demyelinating neuropathy linked to peripheral myelin protein 22 (PMP22) gene deletions. The combination of PMP22 gene mutations with other genetic variants is known to cause a more severe phenotype than expected. We present the case of a patient with severe orthostatic hypotension since 12 years of age, who inherited a PMP22 gene deletion from his father. Genetic double trouble was suspected because of selective sympathetic autonomic disturbances. Through exome-sequencing analysis, we identified two novel mutations in the dopamine beta hydroxylase gene. Moreover, with interactome analysis, we excluded a further influence on the origin of the disease by variants in other genes. This case increases the number of unique patients presenting with dopamine-ß-hydroxylase deficiency and of cases with genetically proven double trouble. Finding the right, complete diagnosis is crucial to obtain adequate medical care and appropriate genetic counseling.

Hypertensive disorders in pregnancy: combined screening by uterine artery Doppler, blood pressure and serum PAPP-A at 11-13 weeks.

OBJECTIVE: To explore if the addition of pregnancy-associated plasma protein-A (PAPP-A) to maternal factors and biophysical markers yields a significant improvement in the detection of hypertensive disorders before the clinical onset of disease. METHODS: Prospective screening study for early preeclampsia (PE), late PE and gestational hypertension (GH) in women attending their first hospital visit at 11(+0)-13(+6) weeks of gestation. The performance of screening for PE and GH by combinations of maternal factors, uterine artery with the lowest pulsatility index (L-PI), mean arterial pressure (MAP) and serum PAPP-A was determined. RESULTS: There were 8061 unaffected controls, 37 of whom developed early PE, 128 with late PE and 140 with GH. Compared to the controls, in early PE and late PE MAP and uterine artery L-PI were increased and PAPP-A was decreased. In GH PAPP-A was not significantly different from controls. In screening for a combination of maternal factors, uterine artery L-PI, MAP and PAPP-A the detection rate of early PE was 83.8%, at a 5% false-positive rate. In the prediction of late PE and GH there was no significant improvement from the addition of PAPP-A to the combination of maternal factors, MAP and uterine artery L-PI. CONCLUSION: Measurement of PAPP-A improves the performance of screening for early PE provided by a combination of maternal factors and biophysical tests at 11-13 weeks.

Three-dimensional quantification of tumor vascularity as a tertiary test after B-mode and power Doppler evaluation for detection of ovarian cancer.

OBJECTIVE: The purpose of this study was to investigate the role of 3-dimensional (3D) quantification of tumor vascularity in the differential diagnosis of pelvic indeterminate masses with a solid appearance or unilocular or multilocular cysts with a solid component showing central vascularization on 2-dimensional power Doppler sonography. METHODS: One hundred fifty-seven consecutive pelvic masses in 153 patients were included in this study and underwent sonography before surgery. Masses that showed a typical benign pattern on B-mode sonography (n = 112) and indeterminate masses with peripheral or absent flow on power Doppler sonography (n = 10) were not evaluated by 3D sonography. Only masses with central vascularization were submitted to 3D power Doppler imaging (n = 35). The following 3D vascular parameters were calculated: relative color and flow measure (similar to the vascularization flow index obtained with other systems). RESULTS: With receiver operating characteristic curve analysis, the best cutoff values for relative color and flow measure were 4.4 and 2.7, respectively. Flow measure had sensitivity of 68% and specificity of 40% in the overall population submitted to 3D power Doppler sonography. Accuracy slightly increased when masses with small papillary projections (<10 mL) were excluded. In this group (n = 22), sensitivity was 83%, and specificity was 50%. CONCLUSIONS: In masses with central vascularization on 2-dimensional power Doppler sonography, the use of 3D quantification of tumor vascularity had low diagnostic accuracy in the detection of adnexal malignancies, although an increase in accuracy in masses with a solid portion of greater than 10 mL was reported.