Chiara Reale

C19orf12 and FA2H Mutations Are Rare in Italian Patients With Neurodegeneration With Brain Iron Accumulation

Neurodegeneration with brain iron accumulation (NBIA) defines a wide spectrum of clinical entities characterized by iron accumulation in specific regions of the brain, predominantly in the basal ganglia. We evaluated the presence of FA2H and C19orf12 mutations in a cohort of 46 Italian patients with early onset NBIA, which were negative for mutations in the PANK2 and PLA2G6 genes. Follow-up molecular genetic and in vitro analyses were then performed. We did not find any mutations in the FA2H gene, although we identified 3 patients carrying novel mutations in the C19orf12 gene. The recent discovery of new genes responsible for NBIA extends the spectrum of the genetic investigation now available for these disorders and makes it possible to delineate a clearer clinical-genetic classification of different forms of this syndrome. A large fraction of patients still remain without a molecular genetics diagnosis, suggesting that additional NBIA genes are still to be discovered.

Novel DYT11 gene mutation in patients without dopaminergic deficit (SWEDD) screened for dystonia

Objective: To test the hypothesis that adult-onset primary dystonia may be the underlying etiology of tremulous patients with clinical diagnosis of Parkinson disease (PD) but without evidence of dopaminergic deficit at nigrostriatal SPECT imaging. Methods: We retrospectively reviewed clinical and imaging data of patients with clinical diagnosis of PD assessed at our tertiary movement disorder clinic, who underwent dopamine transporter SPECT imaging consecutively between 2002 and 2011. Molecular screening for DYT1, DYT5, DYT6, DYT11, and DYT16 dystonia genes was performed in all cases who met the following criteria at the time of SPECT scan: (1) clinical diagnosis of PD; (2) normal dopamine transporter SPECT; (3) asymmetric rest tremor, with or without postural/kinetic component; (4) ≥12-month follow-up; and (5) normal brain MRI. We excluded subjects with (6) overt dystonic features, and (7) head or voice tremor. Results: Twenty-three subjects were eligible for molecular analysis. Positive family history for tremor or PD was present in 45% of probands. We found one patient with a novel heterozygous frameshift mutation in the DYT11 gene (c.1058-1062 delCACCA/p.Gln352fsX376). Electrophysiologic study of tremor revealed that the main contributor was 5- to 6-Hz pseudo-rhythmic myoclonus, primarily involving extensor muscles. In 2 brothers, we found a missense variant in the DYT5 gene (c.334A>G; p.Thr112Ala) of uncertain pathogenicity in humans. Conclusion: Our findings provide further support to the hypothesis that adult-onset monogenic dystonia may underlie a “PD look-alike” clinical phenotype. In addition to dystonic tremor, pseudo-rhythmic myoclonus may be mischaracterized as “rest tremor.”

Expanding the clinical phenotype of DYT5 mutations: Is multiple system atrophy a possible one?

Autosomal dominantly inherited mutations in the GTP cyclohydrolase 1 (GCH1) gene are associated with dopamine-responsive dystonia (DRD), also known as DYT5.1 Rare atypical presentations have been described,2 including adulthood Parkinson disease (PD) with in vivo evidence of nigrostriatal degeneration.3

Novel GNAL mutation with intra-familial clinical heterogeneity: Expanding the phenotype

INTRODUCTION Mutations in GNAL have been associated with adult-onset cranio-cervical dystonia, but a limited number of cases have been reported so far and the clinical spectrum associated with this gene still needs to be fully characterized. METHODS We identified an Italian family with adult-onset, dominantly-inherited dystonia whose members presented with different combinations of dystonia affecting the cervical, oro-mandibular and laryngeal regions associated with prominent tremor in some cases. Pure asymmetric upper limb dystonic tremor was present in one of the members and jerky cervical dystonia was also observed. A dedicate dystonia gene panel (Illumina) was used to screen for dystonia-associated genes and Sanger sequencing was performed to confirm results obtained and to perform segregation analysis. RESULTS A novel single-base mutation in GNAL exon 9 (c.628G>A; p.Asp210Asn) leading to an aminoacidic substitution was identified and confirmed by Sanger sequencing. In silico prediction programmes as well as segregation analysis confirmed its pathogenicity. Clinically, no generalization of dystonia was observed after onset and DBS lead to an excellent motor outcome in two cases. CONCLUSION We report a novel GNAL mutation and expand the clinical spectrum associated with mutations in this gene to comprise pure asymmetric dystonic tremor and a jerky cervical phenotype partially mimicking DYT11 positive cases.

Encephalopathies with intracranial calcification in children: clinical and genetic characterization

BackgroundWe present a group of patients affected by a paediatric onset genetic encephalopathy with cerebral calcification of unknown aetiology studied with Next Generation Sequencing (NGS) genetic analyses.MethodsWe collected all clinical and radiological data. DNA samples were tested by means of a customized gene panel including fifty-nine genes associated with known genetic diseases with cerebral calcification.ResultsWe collected a series of fifty patients. All patients displayed complex and heterogeneous phenotypes mostly including developmental delay and pyramidal signs and less frequently movement disorder and epilepsy. Signs of cerebellar and peripheral nervous system involvement were occasionally present. The most frequent MRI abnormality, beside calcification, was the presence of white matter alterations; calcification was localized in basal ganglia and cerebral white matter in the majority of cases. Sixteen out of fifty patients tested positive for mutations in one of the fifty-nine genes analyzed. In fourteen cases the analyses led to a definite genetic diagnosis while results were controversial in the remaining two.ConclusionsGenetic encephalopathies with cerebral calcification are usually associated to complex phenotypes. In our series, a molecular diagnosis was achieved in 32% of cases, suggesting that the molecular bases of a large number of disorders are still to be elucidated. Our results confirm that cerebral calcification is a good criterion to collect homogeneous groups of patients to be studied by exome or whole genome sequencing; only a very close collaboration between clinicians, neuroradiologists and geneticists can provide better results from these new generation molecular techniques.