Classifying etiology of infantile spasms syndrome in resource-limited settings: A study from the South Asian region

Genetic Advancements in Infantile Epileptic Spasms Syndrome and Opportunities for Precision Medicine

Infantile epileptic spasms syndrome (IESS) is a devastating developmental epileptic encephalopathy (DEE) consisting of epileptic spasms, as well as one or both of developmental regression or stagnation and hypsarrhythmia on EEG. A myriad of aetiologies are associated with the development of IESS; broadly, 60% of cases are thought to be structural, metabolic or infectious in nature, with the remainder genetic or of unknown cause. Epilepsy genetics is a growing field, and over 28 copy number variants and 70 single gene pathogenic variants related to IESS have been discovered to date. While not exhaustive, some of the most commonly reported genetic aetiologies include trisomy 21 and pathogenic variants in genes such as TSC1, TSC2, CDKL5, ARX, KCNQ2, STXBP1 and SCN2A. Understanding the genetic mechanisms of IESS may provide the opportunity to better discern IESS pathophysiology and improve treatments for this condition. This narrative review presents an overview of our current understanding of IESS genetics, with an emphasis on animal models of IESS pathogenesis, the spectrum of genetic aetiologies of IESS (i.e., chromosomal disorders, single-gene disorders, trinucleotide repeat disorders and mitochondrial disorders), as well as available genetic testing methods and their respective diagnostic yields. Future opportunities as they relate to precision medicine and epilepsy genetics in the treatment of IESS are also explored.

Landscape of genetic infantile epileptic spasms syndrome-A multicenter cohort of 124 children from India

OBJECTIVE

Literature on the genotypic spectrum of Infantile Epileptic Spasms Syndrome (IESS) in children is scarce in developing countries. This multicentre collaboration evaluated the genotypic and phenotypic landscape of genetic IESS in Indian children.

METHODS

Between January 2021 and June 2022, this cross-sectional study was conducted at six centers in India. Children with genetically confirmed IESS, without definite structural-genetic and structural-metabolic etiology, were recruited and underwent detailed in-person assessment for phenotypic characterization. The multicentric data on the genotypic and phenotypic characteristics of genetic IESS were collated and analyzed.

RESULTS

Of 124 probands (60% boys, history of consanguinity in 15%) with genetic IESS, 105 had single gene disorders (104 nuclear and one mitochondrial), including one with concurrent triple repeat disorder (fragile X syndrome), and 19 had chromosomal disorders. Of 105 single gene disorders, 51 individual genes (92 variants including 25 novel) were identified. Nearly 85% of children with monogenic nuclear disorders had autosomal inheritance (dominant-55.2%, recessive-14.2%), while the rest had X-linked inheritance. Underlying chromosomal disorders included trisomy 21 (n = 14), Xq28 duplication (n = 2), and others (n = 3). Trisomy 21 (n = 14), ALDH7A1 (n = 10), SCN2A (n = 7), CDKL5 (n = 6), ALG13 (n = 5), KCNQ2 (n = 4), STXBP1 (n = 4), SCN1A (n = 4), NTRK2 (n = 4), and WWOX (n = 4) were the dominant single gene causes of genetic IESS. The median age at the onset of epileptic spasms (ES) and establishment of genetic diagnosis was 5 and 12 months, respectively. Pre-existing developmental delay (94.3%), early age at onset of ES (<6 months; 86.2%), central hypotonia (81.4%), facial dysmorphism (70.1%), microcephaly (77.4%), movement disorders (45.9%) and autistic features (42.7%) were remarkable clinical findings. Seizures other than epileptic spasms were observed in 83 children (66.9%). Pre-existing epilepsy syndrome was identified in 21 (16.9%). Nearly 60% had an initial response to hormonal therapy.

SIGNIFICANCE

Our study highlights a heterogenous genetic landscape and phenotypic pleiotropy in children with genetic IESS.

COVID-19 in Children with West Syndrome: An Ambispective Study

OBJECTIVES

To study the course of West syndrome (WS) and coronavirus disease-19 (COVID-19) in children with WS who contracted SARS-CoV-2 infection.

METHODS

This ambispective study was conducted at a tertiary-care center in North India between December 2020 and August 2021 after approval from the Institute Ethics Committee. Five children with WS, positive for COVID-19 based on RT-PCR, fulfilled the inclusion criteria.

RESULTS

One child with COVID-19 during the first wave was retrospectively included while four children (of the 70 children screened) were prospectively enrolled. The median age at onset of epileptic spasms was 7 mo (2 boys), and that at presentation with COVID-19 was 18.5 mo. Three had underlying acquired structural etiology. Three were in remission following standard therapy, while two had ongoing spasms at the time of COVID-19 illness. During the illness, two of those in remission continued to be in remission while one child had a relapse. The children with ongoing epileptic spasms had variable course [one had persistent spasms and other had transient cessation lasting 3 wk from day 2 of COVID-19 illness, but electroencephalography (on day 8 of COVID-19 illness) continued to show hypsarrhythmia]. Fever was the most typical symptom (and sometimes the only symptom) of COVID-19, with a duration ranging from 1-8 d. Two children had moderate COVID-19 illness requiring hospitalization, while the rest had a mild illness. All the affected children had complete recovery from COVID-19.

CONCLUSION

The severity of COVID-19 illness in children with WS is often mild, while the subsequent course of WS is variable.

The Effect of Smartphone Video on Lead Time to Diagnosis of Infantile Spasms

OBJECTIVE

To assess whether access to smartphone video capture of infantile spasms at initial presentation is associated with improved time to diagnosis and treatment.

METHODS

We conducted a collaborative retrospective cohort study of 80 consecutive infants with confirmed infantile epileptic spasms syndrome initially presenting from 2015 to 2021 at 2 US pediatric centers. Statistical methods used included Mann-Whitney U test to assess the difference in lead times to electroencephalogram (EEG), diagnosis, and treatment between groups with and without video capture. A χ2 analysis was used to assess differences in demographics, clinical characteristics, and treatment outcomes between groups. Multivariate regression analysis was used to account for etiology types and infantile spasms capture on EEG.

RESULTS

Patients with smartphone video infantile spasms capture initially presented a median of 9 days earlier (P = .02), had their first EEG 16 days earlier (P = .007), and were diagnosed and started treatment 17 days earlier (P = .006 and P = .008, respectively) compared with the nonvideo group. The video group had a 25% greater response to initial standard treatment (P = .02) and a 21% greater freedom from infantile spasms at long-term follow-up (P = .03), although this long-term outcome lost statistical significance after adjustment for etiology type (P = .07) and EEG capture of infantile spasms (P = .059).

CONCLUSION

Our findings suggest a benefit of smartphone video capture of infantile spasms in reduced time to diagnosis and initial standard treatment, which are associated with improved treatment response rates. Substantial differences in lead times and treatment response highlight the clinical importance of pediatricians recommending caregivers to obtain smartphone video of events concerning for infantile spasms.

The landscape of infantile epileptic spasms syndrome in South Asia: peculiarities, challenges, and way forward

Infantile Epileptic Spasms Syndrome (IESS), commonly known as West syndrome, is the most common cause of infantile-onset epileptic encephalopathy. There is a peculiar epidemiological profile of IESS in South Asia. Specific features identified were a preponderance of acquired structural aetiology, male gender dominance, a long treatment lag, limited availability of adrenocorticotropic hormone (ACTH) and vigabatrin, and use of carboxymethyl cellulose derivative of ACTH. Because of the significant disease burden and limited resources, there are distinctive challenges to the optimal care of children with IESS in the South Asian region. Also, there are unique opportunities to bridge these challenges and improve outcomes. This review provides an overview of the landscape of IESS in South Asia and highlights its peculiarities, various challenges, and way forward.

Delineating the epilepsy phenotype of NRROS-related microgliopathy: A case report and literature review

BACKGROUND

Negative regulator of reactive oxygen species (NRROS) related microgliopathy, a rare and recently recognized neurodegenerative condition, is caused by pathogenic variants in the NRROS gene, which plays a major role in the regulation of transforming growth factor-beta 1.

METHODS

We report a child presenting with infantile spasms syndrome (ISS) with subsequent progressive neurodegeneration who was identified to harbour a novel likely pathogenic NRROS variant (c.1359del; p.Ser454Alafs*11). The previously published reports of patients with this disorder were also reviewed systematically.

RESULTS

Including our index patient, 11 children (6 girls) were identified in total. Early development was normal in seven of these eleven children. All had a history of drug-resistant epilepsy, with 3 having epileptic spasms. The median age at seizure onset and developmental regression was 12 months, and the median age at death was 36 months. Intracranial calcifications were described in eight of eleven children. Neuroimaging revealed progressive cerebral atrophy and white matter loss in all children. The most common reported genetic variation was c.1981delC; (p.Leu661Serfs*97) observed in two families (likely due to a founder effect).

CONCLUSIONS

Pathogenic variants in NRROS should be suspected in children with neuro-regression and drug-resistant epilepsy including ISS with onset in the first two years of life. Punctate or serpiginous calcifications at the grey-white matter junction and acquired microcephaly are further clues towards the diagnosis.