@article {448, title = {SLC13A5 is the second gene associated with Kohlsch{\"u}tter-T{\"o}nz syndrome.}, journal = {J Med Genet}, volume = {54}, year = {2017}, month = {2017 01}, pages = {54-62}, abstract = {

BACKGROUND: Kohlsch{\"u}tter-T{\"o}nz syndrome (KTZS) is a rare autosomal-recessive disease characterised by epileptic encephalopathy, intellectual disability and amelogenesis imperfecta (AI). It is frequently caused by biallelic mutations in ROGDI. Here, we report on individuals with ROGDI-negative KTZS carrying biallelic SLC13A5 mutations.

METHODS: In the present cohort study, nine individuals from four families with the clinical diagnosis of KTZS and absence of ROGDI mutations as well as one patient with unexplained epileptic encephalopathy were investigated by clinical and dental evaluation, parametric linkage analysis (one family), and exome and/or Sanger sequencing. Dental histological investigations were performed on teeth from individuals with SLC13A5-associated and ROGDI-associated KTZS.

RESULTS: Biallelic mutations in SLC13A5 were identified in 10 affected individuals. Epileptic encephalopathy usually presents in the neonatal and (less frequently) early infantile period. Yellowish to orange discolouration of both deciduous and permanent teeth, as well as wide interdental spaces and abnormal crown forms are major clinical signs of individuals with biallelic SLC13A5 mutations. Histological dental investigations confirmed the clinical diagnosis of hypoplastic AI. In comparison, the histological evaluation of a molar assessed from an individual with ROGDI-associated KTZS revealed hypocalcified AI.

CONCLUSIONS: We conclude that SLC13A5 is the second major gene associated with the clinical diagnosis of KTZS, characterised by neonatal epileptic encephalopathy and hypoplastic AI. Careful clinical and dental delineation provides clues whether ROGDI or SLC13A5 is the causative gene. Hypersensitivity of teeth as well as high caries risk requires individual dental prophylaxis and attentive dental management.

}, keywords = {Alleles, Amelogenesis Imperfecta, Brain Diseases, Cohort Studies, Dementia, Epilepsy, Exome, Female, Genetic Linkage, Genetic Predisposition to Disease, Humans, Male, Membrane Proteins, Mutation, Nuclear Proteins, Pedigree, Symporters, Tooth}, issn = {1468-6244}, doi = {10.1136/jmedgenet-2016-103988}, author = {Schossig, Anna and Bloch-Zupan, Agn{\`e}s and Lussi, Adrian and Wolf, Nicole I and Raskin, Salmo and Cohen, Monika and Giuliano, Fabienne and Jurgens, Julie and Krabichler, Birgit and Koolen, David A and de Macena Sobreira, Nara Lygia and Maurer, Elisabeth and Muller-Bolla, Mich{\`e}le and Penzien, Johann and Zschocke, Johannes and Kapferer-Seebacher, Ines} } @article {16, title = {Periodontal Ehlers-Danlos Syndrome Is Caused by Mutations in C1R and C1S, which Encode Subcomponents C1r and C1s of Complement.}, journal = {Am J Hum Genet}, volume = {99}, year = {2016}, month = {2016 Nov 03}, pages = {1005-1014}, abstract = {

Periodontal Ehlers-Danlos syndrome (pEDS) is an autosomal-dominant disorder characterized by early-onset periodontitis leading to premature loss of teeth, joint hypermobility, and mild skin findings. A locus was mapped to an approximately 5.8 Mb region at 12p13.1 but no candidate gene was identified. In an international consortium we recruited 19 independent families comprising 107 individuals with pEDS to identify the locus, characterize the clinical details in those with defined genetic causes, and try to understand the physiological basis of the condition. In 17 of these families, we identified heterozygous missense or in-frame insertion/deletion mutations in C1R (15 families) or C1S (2 families), contiguous genes in the mapped locus that encode subunits C1r and C1s of the first component of the classical complement pathway. These two proteins form a heterotetramer that then combines with six C1q subunits. Pathogenic variants involve the subunit interfaces or inter-domain hinges of C1r and C1s and are associated with intracellular retention and mild endoplasmic reticulum enlargement. Clinical features of affected individuals in these families include rapidly progressing periodontitis with onset in the teens or childhood, a previously unrecognized lack of attached gingiva, pretibial hyperpigmentation, skin and vascular fragility, easy bruising, and variable musculoskeletal symptoms. Our findings open a connection between the inflammatory classical complement pathway and connective tissue homeostasis.

}, keywords = {Adolescent, Adult, Child, Child, Preschool, Chromosome Mapping, Chromosomes, Human, Pair 12, Complement C1r, Complement C1s, Ehlers-Danlos Syndrome, Endoplasmic Reticulum, Exome, Female, Gene Deletion, Genetic Loci, Humans, Male, Mutation, Missense, Pedigree, Periodontitis, Protein Conformation, Young Adult}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2016.08.019}, author = {Kapferer-Seebacher, Ines and Pepin, Melanie and Werner, Roland and Aitman, Timothy J and Nordgren, Ann and Stoiber, Heribert and Thielens, Nicole and Gaboriaud, Christine and Amberger, Albert and Schossig, Anna and Gruber, Robert and Giunta, Cecilia and Bamshad, Michael and Bj{\"o}rck, Erik and Chen, Christina and Chitayat, David and Dorschner, Michael and Schmitt-Egenolf, Marcus and Hale, Christopher J and Hanna, David and Hennies, Hans Christian and Heiss-Kisielewsky, Irene and Lindstrand, Anna and Lundberg, Pernilla and Mitchell, Anna L and Nickerson, Deborah A and Reinstein, Eyal and Rohrbach, Marianne and Romani, Nikolaus and Schmuth, Matthias and Silver, Rachel and Taylan, Fulya and Vandersteen, Anthony and Vandrovcova, Jana and Weerakkody, Ruwan and Yang, Margaret and Pope, F Michael and Byers, Peter H and Zschocke, Johannes} }