SQSTM1 mutation: Description of the first Tunisian case and literature review

Abstract Background Mutations in SQSTM1 gene have been recently identified as a rare cause of progressive childhood neurodegenerative disorder. So far, only 25 patients from 10 unrelated families were reported. Methods and results We report on the first Tunisian case of an 11‐year‐old girl with cerebellar ataxia, chorea and ophthalmoparesis. Brain MRI was normal. Whole‐exome sequencing revealed a homozygous mutation c.823_824del(p.Ser275Phefs*17) in SQSTM1 gene (GenBank: NM_003900.4). Conclusion By pooling our data to the data of literature, we delineated the phenotypic spectrum and stressed on genetic heterogeneity of this rare neurodegenerative disease

Infantile and childhood onset PLA2G6-associated neurodegeneration in a large North African cohort

Mutations in the PLA2G6 gene are causative of PLA2G6-associated neurodegeneration (PLAN), a spectrum of neurodegenerative conditions including infantile, childhood and adult onset forms

Germline homozygous missense DEPDC5 variants cause severe refractory early-onset epilepsy, macrocephaly and bilateral polymicrogyria

PURPOSE: DEPDC5 (DEP Domain-Containing Protein 5) encodes an inhibitory component of the mTOR pathway and is commonly implicated in sporadic and familial focal epilepsies, both non-lesional and in association with focal cortical dysplasia. Germline pathogenic variants are typically heterozygous and inactivating. We describe a novel phenotype caused by germline biallelic missense variants in DEPDC5. METHODS: Cases were identified clinically. Available records, including MRI and EEG, were reviewed. Genetic testing was performed by whole exome and whole genome sequencing and cascade screening. In addition, immunohistochemistry was performed on skin biopsy. RESULTS: The phenotype was identified in nine children, eight of which are described in detail herein. Six of the children were of Irish Traveller, two of Tunisian and one of Lebanese origin. The Irish Traveller children shared the same DEPDC5 germline homozygous missense variant (p.Thr337Arg), whereas the Lebanese and Tunisian children shared a different germline homozygous variant (p.Arg806Cys). Consistent phenotypic features included extensive bilateral polymicrogyria, congenital macrocephaly and early-onset refractory epilepsy, in keeping with other mTOR-opathies. Eye and cardiac involvement, and severe neutropenia, were also observed in one or more patients. Five of the children died in infancy or childhood, the other four are currently aged between five months and six years. Skin biopsy immunohistochemistry was supportive of hyperactivation of the mTOR pathway. DISCUSSION: The clinical, histopathological and genetic evidence supports a causal role for the homozygous DEPDC5 variants, expanding our understanding of the biology of this gene.Published version, accepted version (12 month embargo), submitted versionThis article is freely available online. Click on the 'Additional Link' above to access the full-text via the publisher's site