@article {735, title = {Detailed genetic characteristics of an international large cohort of patients with Stargardt disease: ProgStar study report 8.}, journal = {Br J Ophthalmol}, volume = {103}, year = {2019}, month = {2019 03}, pages = {390-397}, abstract = {

BACKGROUND/AIMS: To describe the genetic characteristics of the cohort enrolled in the international multicentre progression of Stargardt disease~1 (STGD1) studies (ProgStar) and to~determine geographic differences based on the allele frequency.

METHODS: 345 participants with a clinical diagnosis of STGD1 and harbouring at least one disease-causing ABCA4 variant were enrolled from 9 centres in the USA and Europe. All variants were reviewed and analysis was performed including allele frequency in public databases and pathogenicity predictions. Participants with multiple likely pathogenic variants were classified into four national subgroups (USA, UK, France, Germany), with subsequent comparison analysis of the allele frequency for each prevalent allele.

RESULTS: 211 likely pathogenic variants were identified in the total cohort, including missense (63\%), splice site alteration (18\%), stop (9\%) and others. 50 variants were novel. Exclusively missense variants were detected in 139 (50\%) of 279 patients with multiple pathogenic variants. The three most prevalent variants of these patients with multiple pathogenic variants were p.G1961E (15\%), p.G863A (7\%)~and~c.5461-10 T>C (5\%). Subgroup analysis revealed a statistically significant difference between the four recruiting nations in the allele frequency of nine variants.

CONCLUSIONS: There is a large spectrum of ABCA4 sequence variants, including 50 novel variants, in a well-characterised cohort thereby further adding to the unique allelic heterogeneity in STGD1. Approximately half of the cohort harbours missense variants only, indicating a relatively mild phenotype of the ProgStar cohort. There are significant differences in allele frequencies between nations, although the three most prevalent variants are shared as frequent variants.

}, keywords = {Adolescent, Adult, Age of Onset, Aged, ATP-Binding Cassette Transporters, Child, Child, Preschool, Cohort Studies, Databases, Factual, DNA Mutational Analysis, Female, Gene Frequency, Genotyping Techniques, Geography, Humans, Internationality, Macular Degeneration, Male, Middle Aged, Mutation, Polymerase Chain Reaction}, issn = {1468-2079}, doi = {10.1136/bjophthalmol-2018-312064}, author = {Fujinami, Kaoru and Strauss, Rupert W and Chiang, John Pei-Wen and Audo, Isabelle S and Bernstein, Paul S and Birch, David G and Bomotti, Samantha M and Cideciyan, Artur V and Ervin, Ann-Margret and Marino, Meghan J and Sahel, Jos{\'e}-Alain and Mohand-Said, Saddek and Sunness, Janet S and Traboulsi, Elias I and West, Sheila and Wojciechowski, Robert and Zrenner, Eberhart and Michaelides, Michel and Scholl, Hendrik P N} } @article {344, title = {Complex inheritance of ABCA4 disease: four mutations in a family with multiple macular phenotypes.}, journal = {Hum Genet}, volume = {135}, year = {2016}, month = {2016 Jan}, pages = {9-19}, abstract = {

Over 800 mutations in the ABCA4 gene cause autosomal recessive Stargardt disease. Due to extensive genetic heterogeneity, observed variant-associated phenotypes can manifest tremendous variability of expression. Furthermore, the high carrier frequency of pathogenic ABCA4 alleles in the general population (~1:20) often results in pseudo-dominant inheritance patterns further complicating the diagnosis and characterization of affected individuals. This study describes a genotype/phenotype analysis of an unusual family with multiple macular disease phenotypes spanning across two generations and segregating four distinct ABCA4 mutant alleles. Complete sequencing of ABCA4 discovered two known missense mutations, p.C54Y and p.G1961E. Array comparative genomic hybridization revealed a large novel deletion combined with a small insertion, c.6148-698_c.6670del/insTGTGCACCTCCCTAG, and complete sequencing of the entire ABCA4 genomic locus uncovered a new deep intronic variant, c.302+68C>T. Patients with the p.G1961E mutation had the mildest, confined maculopathy phenotype with peripheral flecks while those with all other mutant allele combinations exhibited a more advanced stage of generalized retinal and choriocapillaris atrophy. This family epitomizes the clinical and genetic complexity of ABCA4-associated diseases. It contained variants from all classes of mutations, in the coding region, deep intronic, both single nucleotide variants and copy number variants that accounted for varying phenotypes segregating in an apparent dominant fashion. Unequivocally defining disease-associated alleles in the ABCA4 locus requires a multifaceted approach that includes advanced mutation detection methods and a thorough analysis of clinical phenotypes.

}, keywords = {Adult, Aged, ATP-Binding Cassette Transporters, Comparative Genomic Hybridization, DNA Copy Number Variations, Electroretinography, Female, High-Throughput Nucleotide Sequencing, Humans, Macula Lutea, Macular Degeneration, Male, Middle Aged, Mutation, Pedigree, Phenotype}, issn = {1432-1203}, doi = {10.1007/s00439-015-1605-y}, author = {Lee, Winston and Xie, Yajing and Zernant, Jana and Yuan, Bo and Bearelly, Srilaxmi and Tsang, Stephen H and Lupski, James R and Allikmets, Rando} } @article {81, title = {Mutations in the nuclear bile acid receptor FXR cause progressive familial intrahepatic cholestasis.}, journal = {Nat Commun}, volume = {7}, year = {2016}, month = {2016 Feb 18}, pages = {10713}, abstract = {

Neonatal cholestasis is a potentially life-threatening condition requiring prompt diagnosis. Mutations in several different genes can cause progressive familial intrahepatic cholestasis, but known genes cannot account for all familial cases. Here we report four individuals from two unrelated families with neonatal cholestasis and mutations in NR1H4, which encodes the farnesoid X receptor (FXR), a bile acid-activated nuclear hormone receptor that regulates bile acid metabolism. Clinical features of severe, persistent NR1H4-related cholestasis include neonatal onset with rapid progression to end-stage liver disease, vitamin K-independent coagulopathy, low-to-normal serum gamma-glutamyl transferase activity, elevated serum alpha-fetoprotein and undetectable liver bile salt export pump (ABCB11) expression. Our findings demonstrate a pivotal function for FXR in bile acid homeostasis and liver protection.

}, keywords = {ATP Binding Cassette Transporter, Subfamily B, Member 11, ATP-Binding Cassette Transporters, Bile Acids and Salts, Cholestasis, Intrahepatic, Female, Humans, Male, Mutation, Receptors, Cytoplasmic and Nuclear, Young Adult}, issn = {2041-1723}, doi = {10.1038/ncomms10713}, author = {Gomez-Ospina, Natalia and Potter, Carol J and Xiao, Rui and Manickam, Kandamurugu and Kim, Mi-Sun and Kim, Kang Ho and Shneider, Benjamin L and Picarsic, Jennifer L and Jacobson, Theodora A and Zhang, Jing and He, Weimin and Liu, Pengfei and Knisely, A S and Finegold, Milton J and Muzny, Donna M and Boerwinkle, Eric and Lupski, James R and Plon, Sharon E and Gibbs, Richard A and Eng, Christine M and Yang, Yaping and Washington, Gabriel C and Porteus, Matthew H and Berquist, William E and Kambham, Neeraja and Singh, Ravinder J and Xia, Fan and Enns, Gregory M and Moore, David D} }