Luigina Spaccini

Genetic testing in benign familial epilepsies of the first year of life: clinical and diagnostic significance

To dissect the genetics of benign familial epilepsies of the first year of life and to assess the extent of the genetic overlap between benign familial neonatal seizures (BFNS), benign familial neonatal‐infantile seizures (BFNIS), and benign familial infantile seizures (BFIS).

Complex Segmental Duplications Mediate a Recurrent dup(X)(p11.22-p11.23) Associated with Mental Retardation, Speech Delay, and EEG Anomalies in Males and Females

Submicroscopic copy-number variations make a considerable contribution to the genetic etiology of human disease. We have analyzed subjects with idiopathic mental retardation (MR) by using whole-genome oligonucleotide-based array comparative genomic hybridization (aCGH) and identified familial and de novo recurrent Xp11.22-p11.23 duplications in males and females with MR, speech delay, and a peculiar electroencephalographic (EEG) pattern in childhood. The size of the duplications ranges from 0.8-9.2 Mb. Most affected females show preferential activation of the duplicated X chromosome. Carriers of the smallest duplication show X-linked recessive inheritance. All other affected individuals present dominant expression and comparable clinical phenotypes irrespective of sex, duplication size, and X-inactivation pattern. The majority of the rearrangements are mediated by recombination between flanking complex segmental duplications. The identification of common clinical features, including the typical EEG pattern, predisposing genomic structure, and peculiar X-inactivation pattern, suggests that duplication of Xp11.22-p11.23 constitutes a previously undescribed syndrome.

Focal seizures with affective symptoms are a major feature of PCDH19 gene-related epilepsy

Purpose:  Mutations of the protocadherin19 gene (PCDH19) cause a female‐related epilepsy of variable severity, with or without mental retardation and autistic features. Despite the increasing number of patients and mutations reported, the epilepsy phenotype associated with PCDH19 mutations is still unclear. We analyzed seizure semiology through ictal video–electroencephalography (EEG) recordings in a large series of patients.

Neonatal suppression-burst without epileptic seizures: expanding the electroclinical phenotype of STXBP1-related, early-onset encephalopathy

Early-onset epileptic encephalopathies (EOEEs) are characterised by epileptic seizures beginning in the first months of life, abnormal background EEG activity, and are associated with severe developmental delay and poor prognosis. Mutations and deletions in the STXBP1 gene are associated with Ohtahara syndrome, also known as “early infantile epilepticencephalopathy”. We report an infant affected by EOEE with a 9q34.11 deletion that encompassed the genes STXBP1 and SPTAN1. The infant presented with neonatal encephalopathy without epileptic seizures and an EEG pattern varying from highly discontinuous to suppression-burst. This was followed by West syndrome at 2 months with atypical hypsarrhythmia and spasms, easily controlled by therapy. Our findings suggest that molecular analysis of STXBP1 should be considered for newborns affected by neonatal encephalopathy associated with a peculiar EEG pattern, even in the absence of neonatal epileptic seizures.

Prenatal/neonatal pathology in two cases of Cornelia de Lange syndrome harboring novel mutations of NIPBL

Purpose: This study reviews prenatal findings in two cases with a suspected diagnosis of Cornelia de Lange Syndrome, a multisystem disorder characterized by somatic defects and mental retardation, that were later confirmed by postmortem examination and molecular testing. Although the correlation between the Cornelia de Lange Syndrome genotype and phenotype is still unclear, preliminary data indicate several severe phenotypic features that are likely to be detected prenatally in NIPBL-mutated patients.Methods: We report on two prenatal/neonatal cases with unusual pathologic findings indicating Cornelia de Lange Syndrome. The first, with suspected Cornelia de Lange Syndrome after a set of typical dysmorphisms was noted by prenatal ultrasound, was confirmed by a physical examination after termination of the pregnancy. The second was diagnosed neonatally on the basis of typical clinical signs. Medical complications led to death within the first month of life.Results: Molecular analysis of NIPBL, the gene that codes for delangin (a component of the cohesin complex), performed postnatally detected two de novo mutations: a missense change (P2056L) in a highly conserved residue and a nonsense alteration (S2490 replaced by a stop codon).Conclusion: We suggest that early diagnosis of Cornelia de Lange Syndrome would be made much easier by the assemblage of a set of prenatal diagnostic features and criteria in Cornelia de Lange Syndrome cases that have been confirmed by direct physical and molecular examinations. We also suggest that Cornelia de Lange Syndrome genotype–phenotype correlations need to be extended to prenatal cases.

Biallelic mutations in the 3′ exonuclease TOE1 cause pontocerebellar hypoplasia and uncover a role in snRNA processing

Deadenylases are best known for degrading the poly(A) tail during mRNA decay. The deadenylase family has expanded throughout evolution and, in mammals, consists of 12 Mg2+-dependent 3′-end RNases with substrate specificity that is mostly unknown. Pontocerebellar hypoplasia type 7 (PCH7) is a unique recessive syndrome characterized by neurodegeneration and ambiguous genitalia. We studied 12 human families with PCH7, uncovering biallelic, loss-of-function mutations in TOE1, which encodes an unconventional deadenylase. toe1-morphant zebrafish displayed midbrain and hindbrain degeneration, modeling PCH-like structural defects in vivo. Surprisingly, we found that TOE1 associated with small nuclear RNAs (snRNAs) incompletely processed spliceosomal. These pre-snRNAs contained 3′ genome-encoded tails often followed by post-transcriptionally added adenosines. Human cells with reduced levels of TOE1 accumulated 3′-end-extended pre-snRNAs, and the immunoisolated TOE1 complex was sufficient for 3′-end maturation of snRNAs. Our findings identify the cause of a neurodegenerative syndrome linked to snRNA maturation and uncover a key factor involved in the processing of snRNA 3′ ends.

Long-term follow-up in two siblings with pyridoxine-dependent seizures associated with a novel ALDH7A1 mutation

Pyridoxine-dependent seizures (PDS) is a rare disorder characterized by seizures resistant to anticonvulsants but controlled by daily pharmacologic doses of pyridoxine. Mutations in the antiquitin (ALDH7A1) gene have recently reported to cause PDS in most of patients. We report the long-term follow-up in two PDS siblings carrying a novel ALDH7A1 mutation.

Clinical findings in a patient with FARS2 mutations and early‐infantile‐encephalopathy with epilepsy

The FARS2 gene encodes the mitochondrial phenylalanyl‐tRNA synthetase and is implicated in autosomal recessive combined oxidative phosphorylation deficiency 14, a clinical condition characterized by infantile onset epilepsy and encephalopathy. Mutations in FARS2 have been reported in only few patients, but a detailed description of seizures, electroencephalographic patterns, magnetic resonance imaging findings, and long‐term follow‐up is still needed. We provide a clinical report of a child with FARS2‐related disease manifesting drug‐resistant infantile spasms associated with focal seizures. By comparative genomic hybridization analysis we identified a heterozygous microdeletion in the short arm of chromosome 6, inherited from the mother, that encompasses the first coding exon of FARS2. By sequencing of the FARS2 gene we identified a variant c.1156C>G; p.(R386G), inherited from the father. By using standard spectrophotometric techniques in skin fibroblasts, we found a combined abnormality of complexes I and IV of the mitochondrial respiratory chain. The main clinical features of the patient included axial hypotonia, mild distal hypertonia, and psychomotor delay. The magnetic resonance imaging showed microcephaly, frontal cerebral atrophy, and signal changes of dentate nuclei. At the age of 3 years and 6 months, the patient was still under treatment with vigabatrin and he has been seizure free for the last 23 months.

Snyder–Robinson syndrome: A novel nonsense mutation in spermine synthase and expansion of the phenotype

Snyder–Robinson syndrome is a rare form of X‐linked intellectual disability caused by mutations in the spermine synthase (SMS) gene, and characterized by intellectual disability, thin habitus with diminished muscle mass, osteoporosis, kyphoscoliosis, facial dysmorphism (asymmetry, full lower lip), long great toes, and nasal or dysarthric speech. Physical signs seem to evolve from childhood to adulthood. We describe the first Italian patient with Snyder–Robinson syndrome and a novel nonsense mutation in SMS (c.200G>A; p.G67X). Apart from the typical features of the syndrome, the index patient presented with an ectopic right kidney and epilepsy from the first year of age that was characterized by focal motor seizures and negative myoclonus. The clinical and molecular evaluation of this family and the review of the literature expand the phenotype of Snyder–Robinson syndrome to include myoclonic or myoclonic‐like seizures (starting even in the first years of life) and renal abnormalities in affected males.

Clinical, neuroradiological and molecular characterization of cerebellar dysplasia with cysts (Poretti-Boltshauser syndrome).

Cerebellar dysplasia with cysts and abnormal shape of the fourth ventricle, in the absence of significant supratentorial anomalies and of muscular involvement, defines recessively inherited Poretti–Boltshauser syndrome (PBS). Clinical features comprise non-progressive cerebellar ataxia, intellectual disability of variable degree, language impairment, ocular motor apraxia and frequent occurrence of myopia or retinopathy. Recently, loss-of-function variants in the LAMA1 gene were identified in six probands with PBS. Here we report the detailed clinical, neuroimaging and genetic characterization of 18 PBS patients from 15 unrelated families. Biallelic LAMA1 variants were identified in 14 families (93%). The only non-mutated proband presented atypical clinical and neuroimaging features, challenging the diagnosis of PBS. Sixteen distinct variants were identified, which were all novel. In particular, the frameshift variant c.[2935delA] recurred in six unrelated families on a shared haplotype, suggesting a founder effect. No LAMA1 variants could be detected in 27 probands with different cerebellar dysplasias or non-progressive cerebellar ataxia, confirming the strong correlate between LAMA1 variants and PBS.