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Introduction Several studies have asserted the existence of a strong and complex genetic component in the determination of psychotic disorders. However, the genetic architecture of these disorders remains poorly understood. GWAS studies conducted over the past decade lead to the identification of only a few low effect associations, and the major part of this heritability remains unexplained, thus calling questioning the hypothesis of «common disease - common variants » for a model involving a large number of rare variants. Aims Here, we studied a multigenerational multiplex family in which co-exist psychotic and mental retardation disorders and a high rate of consanguinity, located in the northwest of Algeria. This study aims to identify inherited rare variants of schizophrenia and mental retardation. Methods This family have received complete clinical (DIGS, DSM-IV creteria) and genealogical investigations and whole exomique sequencing WES (by GAIIx Illumina / HiSeq 2000) that were performed in the departement of genetics in the university hospital of Geneva. Results 07 individus (02 parents and 05 siblings) has been analyzed. The parents were healthy. In siblings, 02 individus had schizophrenia diagnosis, 01 individu had mental retrdation, 01 had both schizophrenia and mental retardation diagnosis and 01 was healthy. Recessive model was retained in this family. For schizophrenia, WES have identified new rare mutations in known genes: rs17057255 (EPHX2), MAF=3%, rs35337118 (SPZ1), MAF=10%, rs2259633 (CCDC67), MAF=17%. Conclusion In total, these highly informative family have identified new genetic variants of schizophrenia. The search for these mutations in contol population in north west of algeria and a wider population of affected individuals with schizophrenia would be useful to validate these data. [ABSTRACT FROM AUTHOR]

Purpose: To document the clinical characteristics and inheritance pattern of epilepsy in multigeneration Algerian families., Methods: Affected members from extended families with familial epilepsy were assessed at the University Hospital of Oran in Algeria. Available medical records, neurological examination, electroencephalography and imaging data were reviewed. The epilepsy type was classified according to the criteria of the International League Against Epilepsy and modes of inheritance were deduced from pedigree analysis., Results: The study population included 40 probands; 23 male (57.5%) and 17 female subjects (42.5%). The mean age of seizure onset was 9.5 ± 6.1 years. According to seizure onset, 16 patients (40%) had focal seizures and 20 (50%) had generalized seizures. Seizure control was achieved for two patients (5%) for 10 years, while 28 (70%) were seizure-free for 3 months. Eleven patients (27.5%) had prior febrile seizures, 12 were diagnosed with psychiatric disorders and four families had syndromic epilepsy. The consanguinity rate among parents of affected was 50% with phenotypic concordance observed in 25 families (62.5%). Pedigree analysis suggested autosomal dominant (AD) inheritance with or without reduced penetrance in 18 families (45%), probable autosomal recessive (AR) inheritance in 14 families (35%), and an X-linked recessive inheritance in one family., Conclusion: This study reveals large Algerian families with multigenerational inheritance of epilepsy. Molecular testing such as exome sequencing would clarify the genetic basis of epilepsy in some of our families., (Copyright © 2015 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.)