Progressive encephalopathy with edema, hypsarrhythmia and optic atrophy (PEHO) syndrome in a Swiss child

Clinical and genetic features of PEHO and PEHO-Like syndromes: A scoping review

Progressive encephalopathy with edema, hypsarrhythmia, and optic atrophy (PEHO) syndrome is a genetic neurological condition characterized by extreme cerebellar atrophy. PEHO-Like syndrome is comparable to PEHO syndrome, with the exception that there is no typical neuro-radiologic or neuro-ophthalmic findings. PEHO spectrum disorders are highly clinically and genetically heterogeneous, and this has challenged their diagnosis. This scoping review aims to summarize and discuss common clinical and genetic features of these syndromes to help future researches. This study was performed according to a six-stage methodology structure and PRISMA guideline. A systematic search of seven databases was performed to find eligible publications prior to June 2020. Articles screening and data extraction were independently performed by two reviewers and quantitative and qualitative analyses were conducted. Thirty-eight articles were identified that fulfill the inclusion criteria. Cerebellar atrophy was the main clinical difference between the two groups but data on optic atrophy and infantile spasms/hypsarrhythmia were not consistent with the previously essential diagnostic criteria. Genetic analysis was performed in several studies, leading to identification of pathogenic variants in different genes that caused these conditions due to different mechanisms. Genetic studies could revolutionize the diagnosis process and our understanding of the etiology of this challenging group of patients by providing targeted sequencing panels and exome- or genome-scale studies in the future.

PEHO syndrome: the endpoint of different genetic epilepsies

Background

Progressive encephalopathy, hypsarrhythmia and optic atrophy (PEHO) has been described as a clinically distinct syndrome. It has been postulated that it is an autosomal recessive condition. However, the aetiology is poorly understood, and the genetic basis of the condition has not been fully elucidated. Our objective was to discover if PEHO syndrome is a single gene disorder.

Method

Children with PEHO and PEHO-like syndrome were recruited. Clinical, neurological and dysmorphic features were recorded; EEG reports and MRI scans were reviewed. Where possible, exome sequencing was carried out first to seek mutations in known early infantile developmental and epileptic encephalopathy (DEE) genes and then to use an agnostic approach to seek novel candidate genes. We sought intra–interfamilial phenotypic correlations and genotype–phenotype correlations when pathological mutations were identified.

Results

Twenty-three children were recruited from a diverse ethnic background, 19 of which were suitable for inclusion. They were similar in many of the core and the supporting features of PEHO, but there was significant variation in MRI and ophthalmological findings, even between siblings with the same mutation. A pathogenic genetic variant was identified in 15 of the 19 children. One further girl’s DNA failed analysis, but her two affected sisters shared confirmed variants. Pathogenic variants were identified in seven different genes.

Conclusions

We found significant clinical and genetic heterogeneity. Given the intrafamily variation demonstrated, we question whether the diagnostic criteria for MRI and ophthalmic findings should be altered. We also question whether PEHO and PEHO-like syndrome represent differing points on a clinical spectrum of the DEE. We conclude that PEHO and PEHO-like syndrome are clinically and genetically diverse entities—and are phenotypic endpoints of many severe genetic encephalopathies.

Deep Brain Stimulation for Status Dystonicus: A Case Series and Review of the Literature

BACKGROUND

Status dystonicus (SD) is a rare and potentially life-threatening complication of primary or secondary dystonia, characterized by acute worsening of dystonic movements. There is no consensus regarding optimal treatment, which may be medical and/or surgical.

METHODS

We present our experience with pallidal deep brain stimulation (DBS) in 5 DYT1-positive patients with SD and provide a review of the literature to examine optimal management.

RESULTS

Of the 5 patients treated with pallidal DBS, all experienced postoperative resolution of their dystonic crisis within a range of 1-21 days. Long-term follow-up resulted in 1 patient returning to preoperative baseline, 3 patients improving from baseline, and 1 patient making a complete recovery. Of the 28 SD patients (including our 5 patients) reported in the literature who were treated with DBS or ablative surgery, 26 experienced cessation of their dystonic crisis with a return to baseline function and, in most cases, clinical improvement.

CONCLUSION

DBS is an effective therapeutic modality for the treatment of SD. In addition to the long-term benefits of stimulation, early and aggressive treatment may improve the overall outcome.

PEHO Syndrome May Represent Phenotypic Expansion at the Severe End of the Early-Onset Encephalopathies

BACKGROUND

Progressive encephalopathy with edema, hypsarrhythmia and optic atrophy (PEHO) syndrome is a distinct neurodevelopmental disorder. Patients without optic nerve atrophy and brain imaging abnormalities but fulfilling other PEHO criteria are often described as a PEHO-like syndrome. The molecular bases of both clinically defined conditions remain unknown in spite of the widespread application of genome analyses in both clinic and research.

METHODS

We enrolled two patients with a prior diagnosis of PEHO and two individuals with PEHO-like syndrome. All four individuals subsequently underwent whole-exome sequencing and comprehensive genomic analysis.

RESULTS

We identified disease-causing mutations in known genes associated with neurodevelopmental disorders including GNAO1 and CDKL5 in two of four individuals. One patient with PEHO syndrome and a de novoGNAO1 mutation was found to have an additional de novo mutation in HESX1 that is associated with optic atrophy.

CONCLUSIONS

We hypothesize that PEHO and PEHO-like syndrome may represent a severe end of the spectrum of the early-onset encephalopathies and, in some instances, its complex phenotype may result from an aggregated effect of mutations at two loci.

Genetic and biologic classification of infantile spasms

Infantile spasms constitute an age-dependent epilepsy, highly associated with cognitive impairment, autism, and movement disorders. Previous classification systems focused on a distinction between symptomatic and cryptogenic etiologies, and have not kept pace with recent discoveries of mutations in genes in key pathways of central nervous system development in patients with infantile spasms. Children with certain genetic syndromes are much likelier to manifest infantile spasms, and we review the literature to propose a genetic classification of these disorders. Children demonstrating genetic associations with infantile spasms also manifest phenotypes beyond epilepsy that may be explained by recent advances in the understanding of underlying biological mechanisms. Therefore we propose a biologic classification of genes highly associated with infantile spasms, and articulate models for infantile spasms pathogenesis based on those data. The two best described pathways of pathogenesis involve abnormalities in the gene regulatory network of gamma-aminobutyric acidergic forebrain development and abnormalities in molecules expressed at the synapse. These genetic and biologic classifications are flexible, and they should encourage much needed progress in syndrome recognition, clinical genetic testing, and the development of new therapies targeting specific pathways of pathogenesis.

Precocious puberty in two girls with PEHO syndrome: a clinical feature not previously described

The authors present 2 girls with progressive encephalopathy, hypsarrhythmia, and optic atrophy syndrome. They describe a novel finding, precocious puberty, a feature not previously reported in this syndrome. The authors also present their clinical features and the results of investigations, including radiological findings, and compare the patients of this report to previously reported cases.

PEHO syndrome: a study of five Argentinian patients

We describe two familial and three nonfamilial cases from Argentina, examined between February 1, 1990-July 31, 2008, who met the diagnostic criteria of progressive encephalopathy, peripheral edema, hypsarrhythmia, and optic atrophy syndrome. All five children were products of normal gestation, although one was premature. Birth was uneventful in all patients. Two patients were twin brothers. During their first neurologic examination, between ages 2-6 months, patients presented with facial dysmorphia, poor visual contact, and generalized hypotonia with poor head control. Microcephaly and swelling of the dorsum of the hands and feet were evident. Hypsarrhythmia was observed in all patients (associated with epileptic spasms in four). Optic atrophy was evident in four cases. Magnetic resonance imaging indicated progressive cerebellum and brainstem atrophy in all cases. Toxoplasmosis, others, rubella, cytomegalovirus, herpes (TORCH), neurometabolic investigations, and karyotype studies produced normal results in all patients. Progressive encephalopathy, peripheral edema, hypsarrhythmia, and optic atrophy syndrome should be considered in infants with neonatal hypotonia, early onset of seizures (especially epileptic spasms), hypsarrhythmia, early loss of visual fixation, profound psychomotor retardation, typical dysmorphy, and progressive cerebellar and brainstem atrophy without a clear etiology. Autosomal recessive inheritance is suspected. Early diagnosis is important for adequate genetic counseling.

Infantile spasms: review of the literature and personal experience

This epileptic disorder has become a classic topic for neuropediatricians and the interest is documented by the large number of publications on this subject.The relative frequency among the epileptic syndromes is an another reason why not only neuropediatricians but also general pediatricians must be fully informed about diagnostic, clinical, imaging and genetic aspects.Early diagnosis is of paramount importance in order to obtain even complete results in patients with so called idiopathic situations. A number of problems are still to be solved. There is no agreement on the type and the schedule of treatment. A common denominator about this problem is not jet available even if some advances in this regard have been accomplished. Of paramount importance is an accurate clinical and laboratory examination as a prerequisite regarding prognosis and results of therapy in every single case.However, even if more than 170 years have elapsed since the first communication of dr. West on the peculiar syndrome that his child was suffering of, the interest of scientists on this subject has now been enriched and rewarded.