@article {826, title = {Molecular diagnosis in recessive pediatric neurogenetic disease can help reduce disease recurrence in families.}, journal = {BMC Med Genomics}, volume = {13}, year = {2020}, month = {2020 05 13}, pages = {68}, abstract = {

BACKGROUND: The causes for thousands of individually rare recessive diseases have been discovered since the adoption of next generation sequencing (NGS). Following the molecular diagnosis in older children in a family, parents could use this information to opt for fetal genotyping in subsequent pregnancies, which could inform decisions about elective termination of pregnancy. The use of NGS diagnostic sequencing in families has not been demonstrated to yield benefit in subsequent pregnancies to reduce recurrence. Here we evaluated whether genetic diagnosis in older children in families supports reduction in recurrence of recessive neurogenetic disease.

METHODS: Retrospective study involving families with a child with a recessive pediatric brain disease (rPBD) that underwent NGS-based molecular diagnosis. Prenatal molecular testing was offered to couples in which a molecular diagnosis was made, to help couples seeking to prevent recurrence. With this information, families made decisions about elective termination. Pregnancies that were carried to term were assessed for the health of child and mother, and compared with historic recurrence risk of recessive disease.

RESULTS: Between 2010 and 2016, 1172 families presented with a child a likely~rPBD, 526 families received a molecular diagnosis, 91 families returned to the clinic with 101 subsequent pregnancies, and 84 opted for fetal genotyping. Sixty tested negative for recurrence for the biallelic mutation~in the fetus, and all, except for one spontaneous abortion, carried to term, and were unaffected at follow-up. Of 24 that genotyped positive~for~the biallelic mutation, 16 were electively terminated, and 8 were carried to term and showed features of disease similar to that of the older~affected sibling(s). Among the 101 pregnancies, disease recurrence in living offspring deviated from the expected 25\% to the observed 12\% ([95\% CI 0{\textperiodcentered}04 to 0{\textperiodcentered}20], p = 0{\textperiodcentered}011).

CONCLUSIONS: Molecular diagnosis in an older child, coupled with prenatal fetal genotyping in subsequent pregnancies and genetic counselling, allows families to make informed decisions to reduce recessive neurogenetic disease recurrence.

}, keywords = {Child, Preschool, Female, Genes, Recessive, Genetic Markers, Genetic Predisposition to Disease, Genetic Testing, Genotype, High-Throughput Nucleotide Sequencing, Humans, Infant, Infant, Newborn, Male, Mutation, Nervous System Diseases, Pedigree, Pregnancy, Prenatal Diagnosis, Recurrence, Retrospective Studies}, issn = {1755-8794}, doi = {10.1186/s12920-020-0714-1}, author = {Issa, Mahmoud Y and Chechlacz, Zinayida and Stanley, Valentina and George, Renee D and McEvoy-Venneri, Jennifer and Belandres, Denice and Elbendary, Hasnaa M and Gaber, Khaled R and Nabil, Ahmed and Abdel-Hamid, Mohamed S and Zaki, MAH S and Gleeson, Joseph G} } @article {500, title = {Genetic variants in components of the NALCN-UNC80-UNC79 ion channel complex cause a broad clinical phenotype (NALCN channelopathies).}, journal = {Hum Genet}, volume = {137}, year = {2018}, month = {2018 Sep}, pages = {753-768}, abstract = {

NALCN is a conserved cation channel, which conducts a permanent sodium leak current and regulates resting membrane potential and neuronal excitability. It is part of a large ion channel complex, the "NALCN channelosome", consisting of multiple proteins including UNC80 and UNC79. The predominant neuronal expression pattern and its function suggest an important role in neuronal function and disease. So far, biallelic NALCN and UNC80 variants have been described in a small number of individuals leading to infantile hypotonia, psychomotor retardation, and characteristic facies 1 (IHPRF1, OMIM 615419) and 2 (IHPRF2, OMIM 616801), respectively. Heterozygous de novo NALCN missense variants in the S5/S6 pore-forming segments lead to congenital contractures of the limbs and face, hypotonia, and developmental delay (CLIFAHDD, OMIM 616266) with some clinical overlap. In this study, we present detailed clinical information of 16 novel individuals with biallelic NALCN variants, 1 individual with a heterozygous de novo NALCN missense variant and an interesting clinical phenotype without contractures, and 12 individuals with biallelic UNC80 variants. We report for the first time a missense NALCN variant~located in the predicted S6 pore-forming unit inherited in an autosomal-recessive manner leading to mild IHPRF1. We show evidence of clinical variability, especially among IHPRF1-affected individuals, and discuss differences between the IHPRF1- and IHPRF2 phenotypes. In summary, we provide a comprehensive overview of IHPRF1 and IHPRF2 phenotypes based on the largest cohort of individuals reported so far and provide additional insights into the clinical phenotypes of these neurodevelopmental diseases to help improve counseling of affected families.

}, keywords = {Adolescent, Adult, Carrier Proteins, Channelopathies, Child, Child, Preschool, Developmental Disabilities, Female, Genetic Markers, Genetic Variation, Humans, Infant, Infant, Newborn, Male, Membrane Proteins, Phenotype, Sodium Channels, Young Adult}, issn = {1432-1203}, doi = {10.1007/s00439-018-1929-5}, author = {Bramswig, Nuria C and Bertoli-Avella, Aida M and Albrecht, Beate and Al Aqeel, Aida I and Alhashem, Amal and Al-Sannaa, Nouriya and Bah, Maissa and Br{\"o}hl, Katharina and Depienne, Christel and Dorison, Nathalie and Doummar, Diane and Ehmke, Nadja and Elbendary, Hasnaa M and Gorokhova, Svetlana and H{\'e}ron, Delphine and Horn, Denise and James, Kiely and Keren, Boris and Kuechler, Alma and Ismail, Samira and Issa, Mahmoud Y and Marey, Isabelle and Mayer, Mich{\`e}le and McEvoy-Venneri, Jennifer and Megarbane, Andre and Mignot, Cyril and Mohamed, Sarar and Nava, Caroline and Philip, Nicole and Ravix, Cecile and Rolfs, Arndt and Sadek, Abdelrahim Abdrabou and Segebrecht, Lara and Stanley, Valentina and Trautman, Camille and Valence, Stephanie and Villard, Laurent and Wieland, Thomas and Engels, Hartmut and Strom, Tim M and Zaki, Maha S and Gleeson, Joseph G and L{\"u}decke, Hermann-Josef and Bauer, Peter and Wieczorek, Dagmar} }