@article {2043, title = {Chorioretinal atrophy following voretigene neparvovec despite the presence of fundus autofluorescence.}, journal = {Mol Genet Genomic Med}, volume = {10}, year = {2022}, month = {2022 Nov}, pages = {e2038}, abstract = {

INTRODUCTION: Leber congenital amaurosis (LCA) type 2, due to disease-causing variants in RPE65, is characterized by severe visual loss in early infancy. Current treatments include voretigene neparvovec-rzyl (VN) for RPE65-associated LCA. Herein, we present the long-term follow-up of a patient treated with VN using quantitative autofluorescence (488\ nm excitation).

CASE REPORT: A 9-year-old girl with a diagnosis of LCA with biallelic variants in RPE65 presented for evaluation. The patient underwent VN treatment at the age of 11. The patient returned to clinic at age of 19 at which time imaging revealed evidence of chorioretinal atrophy. Quantitative autofluorescence performed prior to gene therapy and at 6- and 8-year follow-up revealed a central area of fundus autofluorescence.

DISCUSSION: This case report demonstrates acquisition of fundus autofluorescence at 6- and 8-year follow-up despite the development of chorioretinal atrophy.

}, keywords = {Atrophy, Child, cis-trans-Isomerases, Female, Humans, Leber Congenital Amaurosis, Mutation, Retinal Degeneration}, issn = {2324-9269}, doi = {10.1002/mgg3.2038}, author = {Kolesnikova, Masha and Lima de Carvalho, Jose Ronaldo and Parmann, Rait and Kim, Angela H and Mahajan, Vinit B and Tsang, Stephen H and Sparrow, Janet R} } @article {2020, title = {Expanding the phenotype of TTLL5-associated retinal dystrophy: a case series.}, journal = {Orphanet J Rare Dis}, volume = {17}, year = {2022}, month = {2022 04 01}, pages = {146}, abstract = {

BACKGROUND: Inherited retinal dystrophies describe a heterogeneous group of retinal diseases that lead to the irreversible degeneration of rod and cone photoreceptors and eventual blindness. Recessive loss-of-function mutations in Tubulin Tyrosine Ligase Like 5 (TTLL5) represent a recently described cause of inherited cone-rod and cone dystrophy. This study describes the unusual phenotypes of three patients with autosomal recessive mutations in TTLL5. Examination of these patients included funduscopic evaluation, spectral-domain optical coherence tomography, short-wavelength autofluorescence, and full-field electroretinography (ffERG). Genetic diagnoses were confirmed using whole exome capture. Protein modeling of the identified variants was performed to explore potential genotype-phenotype correlations.

RESULTS: Genetic testing revealed five novel variants in TTLL5 in three unrelated patients with retinal dystrophy. Clinical imaging demonstrated features of sectoral cone-rod dystrophy and cone dystrophy, with phenotypic variability seen across all three patients. One patient also developed high-frequency hearing loss during a similar time period as the onset of retinal disease, potentially suggestive of a syndromic disorder. Retinal structure findings were corroborated with functional measures including ffERG findings that supported these diagnoses. Modeling of the five variants suggest that they cause different effects on protein function, providing a potential reason for genotype-phenotype correlation in these patients.

CONCLUSIONS: The authors report retinal phenotypic findings in three unrelated patients with novel mutations causing autosomal recessive TTLL5-mediated retinal dystrophy. These findings broaden the understanding of the phenotypes associated with TTLL5-mediated retinal disease and suggest that mutations in TTLL5 should be considered as a potential cause of sectoral retinal dystrophy in addition to cone-rod and cone dystrophies.

}, keywords = {Carrier Proteins, Electroretinography, Genetic Association Studies, Humans, Mutation, Phenotype, Retinal Dystrophies}, issn = {1750-1172}, doi = {10.1186/s13023-022-02295-9}, author = {Oh, Jin Kyun and Vargas Del Valle, Jos{\'e} G and Lima de Carvalho, Jose Ronaldo and Sun, Young Joo and Levi, Sarah R and Ryu, Joseph and Yang, Jing and Nagasaki, Takayuki and Emanuelli, Andres and Rasool, Nailyn and Allikmets, Rando and Sparrow, Janet R and Izquierdo, Natalio J and Duncan, Jacque L and Mahajan, Vinit B and Tsang, Stephen H} } @article {2047, title = {Therapeutic Window for Phosphodiesterase 6-Related Retinitis Pigmentosa.}, journal = {JAMA Ophthalmol}, volume = {137}, year = {2019}, month = {2019 Jun 01}, pages = {679-680}, keywords = {Cone-Rod Dystrophies, Cyclic Nucleotide Phosphodiesterases, Type 6, Eye Proteins, Follow-Up Studies, Humans, Mutation, Retinitis Pigmentosa}, issn = {2168-6173}, doi = {10.1001/jamaophthalmol.2018.6381}, author = {Wang, Nan-Kai and Mahajan, Vinit B and Tsang, Stephen H} } @article {635, title = {Recessive coding and regulatory mutations in FBLIM1 underlie the pathogenesis of chronic recurrent multifocal osteomyelitis (CRMO).}, journal = {PLoS One}, volume = {12}, year = {2017}, month = {2017}, pages = {e0169687}, abstract = {

Chronic recurrent multifocal osteomyelitis (CRMO) is a rare, pediatric, autoinflammatory disease characterized by bone pain due to sterile osteomyelitis, and is often accompanied by psoriasis or inflammatory bowel disease. There are two syndromic forms of CRMO, Majeed syndrome and DIRA, for which the genetic cause is known. However, for the majority of cases of CRMO, the genetic basis is unknown. Via whole-exome sequencing, we detected a homozygous mutation in the filamin-binding domain of FBLIM1 in an affected child with consanguineous parents. Microarray analysis of bone marrow macrophages from the CRMO murine model (cmo) determined that the Fblim1 ortholog is the most differentially expressed gene, downregulated over 20-fold in the cmo mouse. We sequenced FBLIM1 in 96 CRMO subjects and found a second proband with a novel frameshift mutation in exon 6 and a rare regulatory variant. In SaOS2 cells, overexpressing the regulatory mutation showed the flanking region acts as an enhancer, and the mutation ablates enhancer activity. Our data implicate FBLIM1 in the pathogenesis of sterile bone inflammation and our findings suggest CRMO is a disorder of chronic inflammation and imbalanced bone remodeling.

}, keywords = {Amino Acid Sequence, Animals, Cell Adhesion Molecules, Cell Line, Tumor, Child, Cytoskeletal Proteins, Female, Genes, Recessive, Humans, Interleukin-10, Mice, Mutation, Osteomyelitis, Promoter Regions, Genetic, Sequence Homology, Amino Acid}, issn = {1932-6203}, doi = {10.1371/journal.pone.0169687}, author = {Cox, Allison J and Darbro, Benjamin W and Laxer, Ronald M and Velez, Gabriel and Bing, Xinyu and Finer, Alexis L and Erives, Albert and Mahajan, Vinit B and Bassuk, Alexander G and Ferguson, Polly J} } @article {671, title = {Autism Linked to Increased Oncogene Mutations but Decreased Cancer Rate.}, journal = {PLoS One}, volume = {11}, year = {2016}, month = {2016}, pages = {e0149041}, abstract = {

Autism spectrum disorder (ASD) is one phenotypic aspect of many monogenic, hereditary cancer syndromes. Pleiotropic effects of cancer genes on the autism phenotype could lead to repurposing of oncology medications to treat this increasingly prevalent neurodevelopmental condition for which there is currently no treatment. To explore this hypothesis we sought to discover whether autistic patients more often have rare coding, single-nucleotide variants within tumor suppressor and oncogenes and whether autistic patients are more often diagnosed with neoplasms. Exome-sequencing data from the ARRA Autism Sequencing Collaboration was compared to that of a control cohort from the Exome Variant Server database revealing that rare, coding variants within oncogenes were enriched for in the ARRA ASD cohort (p<1.0 x 10(-8)). In contrast, variants were not significantly enriched in tumor suppressor genes. Phenotypically, children and adults with ASD exhibited a protective effect against cancer, with a frequency of 1.3\% vs. 3.9\% (p<0.001), but the protective effect decreased with age. The odds ratio of neoplasm for those with ASD relative to controls was 0.06 (95\% CI: 0.02, 0.19; p<0.0001) in the 0 to 14 age group; 0.35 (95\% CI: 0.14, 0.87; p = 0.024) in the 15 to 29 age group; 0.41 (95\% CI: 0.15, 1.17; p = 0.095) in the 30 to 54 age group; and 0.49 (95\% CI: 0.14, 1.74; p = 0.267) in those 55 and older. Both males and females demonstrated the protective effect. These findings suggest that defects in cellular proliferation, and potentially senescence, might influence both autism and neoplasm, and already approved drugs targeting oncogenic pathways might also have therapeutic value for treating autism.

}, keywords = {Adolescent, Adult, Autism Spectrum Disorder, Child, Child, Preschool, Female, Genes, Tumor Suppressor, Genetic Predisposition to Disease, Humans, Infant, Male, Middle Aged, Mutation, Neoplasms, Oncogenes, Prevalence, Young Adult}, issn = {1932-6203}, doi = {10.1371/journal.pone.0149041}, author = {Darbro, Benjamin W and Singh, Rohini and Zimmerman, M Bridget and Mahajan, Vinit B and Bassuk, Alexander G} } @article {659, title = {BESTROPHIN1 mutations cause defective chloride conductance in patient stem cell-derived RPE.}, journal = {Hum Mol Genet}, volume = {25}, year = {2016}, month = {2016 07 01}, pages = {2672-2680}, abstract = {

Bestrophin1 (BEST1) is expressed in human retinal pigment epithelium (RPE) and mutations in the BEST1 gene commonly cause retinal dysfunction and macular degeneration. BEST1 is presumed to assemble into a calcium-activated chloride channel and be involved in chloride transport but there is no direct evidence in live human RPE cells to support this idea. To test whether BEST1 functions as a chloride channel in living tissue, BEST1-mutant RPE (R218H, L234P, A243T) were generated from patient-derived induced pluripotent stem cells and compared with wild-type RPE in a retinal environment, using a biosensor that visualizes calcium-induced chloride ion flux in the cell. Calcium stimulation elicited chloride ion export in normal RPE but not in RPE derived from three patients with BEST1 mutations. These data, along with three-dimensional modeling, provide evidence that BEST1 assembles into a key calcium-sensing chloride channel in human RPE.

}, keywords = {Bestrophins, Calcium Signaling, Chloride Channels, Chlorides, Eye Proteins, Humans, Induced Pluripotent Stem Cells, Mutation, Retinal Pigment Epithelium, Vitelliform Macular Dystrophy}, issn = {1460-2083}, doi = {10.1093/hmg/ddw126}, author = {Moshfegh, Yasmin and Velez, Gabriel and Li, Yao and Bassuk, Alexander G and Mahajan, Vinit B and Tsang, Stephen H} } @article {655, title = {CRISPR Repair Reveals Causative Mutation in a Preclinical Model of Retinitis Pigmentosa.}, journal = {Mol Ther}, volume = {24}, year = {2016}, month = {2016 08}, pages = {1388-94}, abstract = {

Massive parallel sequencing enables identification of numerous genetic variants in mutant organisms, but determining pathogenicity of any one mutation can be daunting. The most commonly studied preclinical model of retinitis pigmentosa called the "rodless" (rd1) mouse is homozygous for two mutations: a nonsense point mutation (Y347X) and an intronic insertion of a leukemia virus (Xmv-28). Distinguishing which mutation causes retinal degeneration is still under debate nearly a century after the discovery of this model organism. Here, we performed gene editing using the CRISPR/Cas9 system and demonstrated that the Y347X mutation is the causative variant of disease. Genome editing in the first generation produced animals that were mosaic for the corrected allele but still showed neurofunction preservation despite low repair frequencies. Furthermore, second-generation CRISPR-repaired mice showed an even more robust rescue and amelioration of the disease. This predicts excellent outcomes for gene editing in diseased human tissue, as Pde6b, the mutated gene in rd1 mice, has an orthologous intron-exon relationship comparable with the human PDE6B gene. Not only do these findings resolve the debate surrounding the source of neurodegeneration in the rd1 model, but they also provide the first example of homology-directed recombination-mediated gene correction in the visual system.

}, keywords = {Animals, Clustered Regularly Interspaced Short Palindromic Repeats, CRISPR-Cas Systems, Cyclic Nucleotide Phosphodiesterases, Type 6, Disease Models, Animal, DNA Repair, Electroretinography, Exons, Gene Editing, Genetic Loci, Homologous Recombination, Mice, Mice, Transgenic, Mutation, Photoreceptor Cells, Vertebrate, Retinal Degeneration, Retinitis Pigmentosa, RNA, Guide}, issn = {1525-0024}, doi = {10.1038/mt.2016.107}, author = {Wu, Wen-Hsuan and Tsai, Yi-Ting and Justus, Sally and Lee, Ting-Ting and Zhang, Lijuan and Lin, Chyuan-Sheng and Bassuk, Alexander G and Mahajan, Vinit B and Tsang, Stephen H} } @article {637, title = {Reprogramming metabolism by targeting sirtuin 6 attenuates retinal degeneration.}, journal = {J Clin Invest}, volume = {126}, year = {2016}, month = {2016 Dec 01}, pages = {4659-4673}, abstract = {

Retinitis pigmentosa (RP) encompasses a diverse group of Mendelian disorders leading to progressive degeneration of rods and then cones. For reasons that remain unclear, diseased RP photoreceptors begin to deteriorate, eventually leading to cell death and, consequently, loss of vision. Here, we have hypothesized that RP associated with mutations in phosphodiesterase-6 (PDE6) provokes a metabolic aberration in rod cells that promotes the pathological consequences of elevated cGMP and Ca2+, which are induced by the Pde6 mutation. Inhibition of sirtuin 6 (SIRT6), a histone deacetylase repressor of glycolytic flux, reprogrammed rods into perpetual glycolysis, thereby driving the accumulation of biosynthetic intermediates, improving outer segment (OS) length, enhancing photoreceptor survival, and preserving vision. In mouse retinae lacking Sirt6, effectors of glycolytic flux were dramatically increased, leading to upregulation of key intermediates in glycolysis, TCA cycle, and glutaminolysis. Both transgenic and AAV2/8 gene therapy-mediated ablation of Sirt6 in rods provided electrophysiological and anatomic rescue of both rod and cone photoreceptors in a preclinical model of RP. Due to the extensive network of downstream effectors of Sirt6, this study motivates further research into the role that these pathways play in retinal degeneration. Because reprogramming metabolism by enhancing glycolysis is not gene specific, this strategy may be applicable to a wide range of neurodegenerative disorders.

}, keywords = {Animals, Cellular Reprogramming, Cellular Reprogramming Techniques, Citric Acid Cycle, Cyclic GMP, Cyclic Nucleotide Phosphodiesterases, Type 6, Dependovirus, Disease Models, Animal, Eye Proteins, Genetic Therapy, Glycolysis, Mice, Mice, Mutant Strains, Mutation, Retinal Rod Photoreceptor Cells, Retinitis Pigmentosa, Sirtuins, Transduction, Genetic}, issn = {1558-8238}, doi = {10.1172/JCI86905}, author = {Zhang, Lijuan and Du, Jianhai and Justus, Sally and Hsu, Chun-Wei and Bonet-Ponce, Luis and Wu, Wen-Hsuan and Tsai, Yi-Ting and Wu, Wei-Pu and Jia, Yading and Duong, Jimmy K and Mahajan, Vinit B and Lin, Chyuan-Sheng and Wang, Shuang and Hurley, James B and Tsang, Stephen H} } @article {669, title = {Response to Sandford et~al.: PRICKLE2 Variants in Epilepsy: A Call for Precision Medicine.}, journal = {Am J Hum Genet}, volume = {98}, year = {2016}, month = {2016 Mar 03}, pages = {590-591}, keywords = {Animals, Carrier Proteins, DNA-Binding Proteins, Drosophila Proteins, Female, Humans, Male, Mutation, Nerve Tissue Proteins, Seizures, Tumor Suppressor Proteins, Zebrafish Proteins}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2016.02.002}, author = {Mahajan, Vinit B and Bassuk, Alexander G} } @article {713, title = {Quantitative autofluorescence as a clinical tool for expedited differential diagnosis of retinal degeneration.}, journal = {JAMA Ophthalmol}, volume = {133}, year = {2015}, month = {2015 Feb}, pages = {219-20}, keywords = {Adult, ATP-Binding Cassette Transporters, Diagnosis, Differential, DNA, DNA Mutational Analysis, Fluorescein Angiography, Fundus Oculi, Humans, Male, Mutation, Optical Imaging, Retina, Retinal Degeneration, Retinitis Pigmentosa}, issn = {2168-6173}, doi = {10.1001/jamaophthalmol.2014.4507}, author = {Marsiglia, Marcela and Lee, Winston and Mahajan, Vinit B and Zernant, Jana and Delori, Fran{\c c}ois C and Tsang, Stephen H and Sparrow, Janet R} } @article {115, title = {Calpain-5 mutations cause autoimmune uveitis, retinal neovascularization, and photoreceptor degeneration.}, journal = {PLoS Genet}, volume = {8}, year = {2012}, month = {2012}, pages = {e1003001}, abstract = {

Autosomal dominant neovascular inflammatory vitreoretinopathy (ADNIV) is an autoimmune condition of the eye that sequentially mimics uveitis, retinitis pigmentosa, and proliferative diabetic retinopathy as it progresses to complete blindness. We identified two different missense mutations in the CAPN5 gene in three ADNIV kindreds. CAPN5 encodes calpain-5, a calcium-activated cysteine protease that is expressed in retinal photoreceptor cells. Both mutations cause mislocalization from the cell membrane to the cytosol, and structural modeling reveals that both mutations lie within a calcium-sensitive domain near the active site. CAPN5 is only the second member of the large calpain gene family to cause a human Mendelian disorder, and this is the first report of a specific molecular cause for autoimmune eye disease. Further investigation of these mutations is likely to provide insight into the pathophysiologic mechanisms of common diseases ranging from autoimmune disorders to diabetic retinopathy.

}, keywords = {Amino Acid Sequence, Base Sequence, Calpain, Cell Line, Cells, Cultured, Choroid Diseases, Exome, Exons, Eye Diseases, Hereditary, Female, Gene Expression, Genetic Linkage, Humans, Male, Models, Molecular, Molecular Sequence Data, Mutation, Pedigree, Phenotype, Photoreceptor Cells, Vertebrate, Protein Conformation, Protein Transport, Retinal Degeneration, Sequence Alignment}, author = {Mahajan, Vinit B and Skeie, Jessica M and Bassuk, Alexander G and Fingert, John H and Braun, Terry A and Daggett, Heather T and Folk, James C and Sheffield, Val C and Stone, Edwin M} } @article {117, title = {Disruption of mouse Cenpj, a regulator of centriole biogenesis, phenocopies Seckel syndrome.}, journal = {PLoS Genet}, volume = {8}, year = {2012}, month = {2012}, pages = {e1003022}, abstract = {

Disruption of the centromere protein J gene, CENPJ (CPAP, MCPH6, SCKL4), which is a highly conserved and ubiquitiously expressed centrosomal protein, has been associated with primary microcephaly and the microcephalic primordial dwarfism disorder Seckel syndrome. The mechanism by which disruption of CENPJ causes the proportionate, primordial growth failure that is characteristic of Seckel syndrome is unknown. By generating a hypomorphic allele of Cenpj, we have developed a mouse (Cenpj(tm/tm)) that recapitulates many of the clinical features of Seckel syndrome, including intrauterine dwarfism, microcephaly with memory impairment, ossification defects, and ocular and skeletal abnormalities, thus providing clear confirmation that specific mutations of CENPJ can cause Seckel syndrome. Immunohistochemistry revealed increased levels of DNA damage and apoptosis throughout Cenpj(tm/tm) embryos and adult mice showed an elevated frequency of micronucleus induction, suggesting that Cenpj-deficiency results in genomic instability. Notably, however, genomic instability was not the result of defective ATR-dependent DNA damage signaling, as is the case for the majority of genes associated with Seckel syndrome. Instead, Cenpj(tm/tm) embryonic fibroblasts exhibited irregular centriole and centrosome numbers and mono- and multipolar spindles, and many were near-tetraploid with numerical and structural chromosomal abnormalities when compared to passage-matched wild-type cells. Increased cell death due to mitotic failure during embryonic development is likely to contribute to the proportionate dwarfism that is associated with CENPJ-Seckel syndrome.

}, keywords = {Animals, Apoptosis, Centrioles, DNA Damage, Dwarfism, Embryonic Development, Genomic Instability, Mice, Mice, Transgenic, Microcephaly, Microtubule-Associated Proteins, Mitosis, Mitotic Spindle Apparatus, Mutation, Signal Transduction}, author = {McIntyre, Rebecca E and Lakshminarasimhan Chavali, Pavithra and Ismail, Ozama and Carragher, Damian M and Sanchez-Andrade, Gabriela and Forment, Josep V and Fu, Beiyuan and Del Castillo Velasco-Herrera, Martin and Edwards, Andrew and van der Weyden, Louise and Yang, Fengtang and Ramirez-Solis, Ramiro and Estabel, Jeanne and Gallagher, Ferdia A and Logan, Darren W and Arends, Mark J and Tsang, Stephen H and Mahajan, Vinit B and Scudamore, Cheryl L and White, Jacqueline K and Jackson, Stephen P and Gergely, Fanni and Adams, David J} } @article {149, title = {Mutations in prickle orthologs cause seizures in flies, mice, and humans.}, journal = {American journal of human genetics}, volume = {88}, year = {2011}, month = {2011 Feb 11}, pages = {138-49}, abstract = {

Epilepsy is heritable, yet few causative gene mutations have been identified, and thus far no human epilepsy gene mutations have been found to produce seizures in invertebrates. Here we show that mutations in prickle genes are associated with seizures in humans, mice, and flies. We identified human epilepsy patients with heterozygous mutations in either PRICKLE1 or PRICKLE2. In overexpression assays in zebrafish, prickle mutations resulted in aberrant prickle function. A seizure phenotype was present in the Prickle1-null mutant mouse, two Prickle1 point mutant (missense and nonsense) mice, and a Prickle2-null mutant mouse. Drosophila with prickle mutations displayed seizures that were responsive to anti-epileptic medication, and homozygous mutant embryos showed neuronal defects. These results suggest that prickle mutations have caused seizures throughout evolution.

}, keywords = {Animals, Blotting, Western, Brain, Calcium, Carrier Proteins, DNA-Binding Proteins, Drosophila melanogaster, Drosophila Proteins, Embryo, Nonmammalian, Epilepsies, Myoclonic, Female, Heterozygote, Humans, Immunoenzyme Techniques, In Situ Hybridization, Male, Mice, Mice, Knockout, Mutation, Nerve Tissue Proteins, Phenotype, Reverse Transcriptase Polymerase Chain Reaction, RNA, Messenger, Seizures, Tumor Suppressor Proteins, Zebrafish, Zebrafish Proteins}, author = {Tao, Hirotaka and Manak, J Robert and Sowers, Levi and Mei, Xue and Kiyonari, Hiroshi and Abe, Takaya and Dahdaleh, Nader S and Yang, Tian and Wu, Shu and Chen, Shan and Fox, Mark H and Gurnett, Christina and Montine, Thomas and Bird, Thomas and Shaffer, Lisa G and Rosenfeld, Jill A and McConnell, Juliann and Madan-Khetarpal, Suneeta and Berry-Kravis, Elizabeth and Griesbach, Hilary and Saneto, Russell P and Scott, Matthew P and Antic, Dragana and Reed, Jordan and Boland, Riley and Ehaideb, Salleh N and El-Shanti, Hatem and Mahajan, Vinit B and Ferguson, Polly J and Axelrod, Jeffrey D and Lehesjoki, Anna-Elina and Fritzsch, Bernd and Slusarski, Diane C and Wemmie, John and Ueno, Naoto and Bassuk, Alexander G} } @article {157, title = {Collagen XVIII mutation in Knobloch syndrome with acute lymphoblastic leukemia.}, journal = {American journal of medical genetics. Part A}, volume = {152A}, year = {2010}, month = {2010 Nov}, pages = {2875-9}, abstract = {

Knobloch syndrome (KNO) is caused by mutations in the collagen XVIII gene (COL18A1) and patients develop encephalocele and vitreoretinal degeneration. Here, we report an El Salvadorian family where two sisters showed features of KNO. One of the siblings also developed acute lymphoblastic leukemia. DNA sequencing of COL18A1 revealed a homozygous, 2-bp deletion (c3514-3515delCT) in exon 41, which leads to abnormal collagen XVIII and deficiency of its proteolytic cleavage product endostatin. KNO patients with mutations in COL18A1 may be at risk for endostatin-related conditions including malignancy.

}, keywords = {Base Sequence, Child, Child, Preschool, Collagen Type XVIII, DNA Mutational Analysis, Encephalocele, Eye Abnormalities, Family, Female, Humans, Infant, Magnetic Resonance Imaging, Male, Molecular Sequence Data, Mutation, Pedigree, Precursor Cell Lymphoblastic Leukemia-Lymphoma, Retinal Detachment}, author = {Mahajan, Vinit B and Olney, Ann Haskins and Garrett, Penny and Chary, Ajit and Dragan, Ecaterina and Lerner, Gary and Murray, Jeffrey and Bassuk, Alexander G} } @article {177, title = {Transgenic mice carrying the H258N mutation in the gene encoding the beta-subunit of phosphodiesterase-6 (PDE6B) provide a model for human congenital stationary night blindness.}, journal = {Human mutation}, volume = {28}, year = {2007}, month = {2007 Mar}, pages = {243-54}, abstract = {

Mutations in the beta-subunit of cGMP-phosphodiesterase (PDE6beta) can lead to either progressive retinal disease, such as human retinitis pigmentosa (RP), or stationary disease, such as congenital stationary night blindness (CSNB). Individuals with CSNB in the Rambusch pedigree were found to carry the H258N allele of PDE6B (MIM$\#$ 180072); a similar mutation was not found in RP patients. This report describes an individual carrying the H258N allele, who presented with generalized retinal dysfunction affecting the rod system and a locus of dysfunction at the rod-bipolar interface. Also described are preclinical studies in which transgenic mice with the H258N allele were generated to study the pathophysiological mechanisms of CSNB. While Pde6b(rd1)/Pde6b(rd1) mice have severe photoreceptor degeneration, as in human RP, the H258N transgene rescued these cells. The cGMP-PDE6 activity of dark-adapted H258N mice showed an approximate three-fold increase in the rate of retinal cGMP hydrolysis: from 130.1 nmol x min(-1) x nmol(-1) rhodopsin in wild-type controls to 319.2 nmol x min(-1) x nmol(-1) rhodopsin in mutants, consistent with the hypothesis that inhibition of the PDE6beta activity by the regulatory PDE6gamma subunit is blocked by this mutation. In the albino (B6CBA x FVB) F2 hybrid background, electroretinograms (ERG) from H258N mice were similar to those obtained from affected Rambusch family members, as well as humans with the most common form of CSNB (X-linked), demonstrating a selective loss of the b-wave with relatively normal a-waves. When the H258N allele was introduced into the DBA background, there was no evidence of selective reduction in b-wave amplitudes; rather a- and b-wave amplitudes were both reduced. Thus, factors other than the PDE6B mutation itself could contribute to the variance of an electrophysiological response. Therefore, caution is advisable when interpreting physiological phenotypes associated with the same allele on different genetic backgrounds. Nevertheless, such animals should be of considerable value in further studies of the molecular pathology of CSNB.

}, keywords = {Adult, Animals, Cyclic Nucleotide Phosphodiesterases, Type 6, Disease Models, Animal, DNA Mutational Analysis, Electroretinography, Female, Humans, Male, Mice, Mice, Inbred DBA, Mice, Transgenic, Mutation, Night Blindness, Phosphoric Diester Hydrolases, Retinal Degeneration, Transgenes}, author = {Tsang, Stephen H and Woodruff, Michael L and Jun, Lin and Mahajan, Vinit and Yamashita, Clyde K and Pedersen, Robert and Lin, Chyuan-Sheng and Goff, Stephen P and Rosenberg, Thomas and Larsen, Michael and Farber, Debora B and Nusinowitz, Steven} }