@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 {129, title = {CRB1-Related Maculopathy With Cystoid Macular Edema.}, journal = {JAMA Ophthalmol}, volume = {133}, year = {2015}, month = {2015 Nov}, pages = {1357-60}, keywords = {Administration, Topical, Carbonic Anhydrase Inhibitors, Child, Diseases in Twins, DNA Mutational Analysis, Electroretinography, Eye Proteins, Female, Fluorescein Angiography, Humans, Macular Edema, Membrane Proteins, Mutation, Nerve Tissue Proteins, Ophthalmic Solutions, Retinal Dystrophies, Sulfonamides, Thiophenes, Tomography, Optical Coherence, Twins, Monozygotic, Visual Acuity}, issn = {2168-6173}, doi = {10.1001/jamaophthalmol.2015.2814}, author = {Wolfson, Yulia and Applegate, Carolyn D and Strauss, Rupert W and Han, Ian C and Scholl, Hendrik P} } @article {192, title = {Whole Exome Sequencing Identifies an Adult-Onset Case of Methylmalonic Aciduria and Homocystinuria Type C (cblC) with Non-Syndromic Bull{\textquoteright}s Eye Maculopathy.}, journal = {Ophthalmic Genet}, volume = {36}, year = {2015}, month = {2015}, pages = {270-5}, abstract = {

BACKGROUND: Methylmalonic aciduria and homocystinuria type C (cblC), a disorder of vitamin B12 (cobalamin) metabolism caused by mutations in the MMACHC gene, presents with many systemic symptoms, including neurological, cognitive, psychiatric, and thromboembolic events. Retinal phenotypes, including maculopathy, pigmentary retinopathy, and optic atrophy are common in early onset form of the disease but are rare in adult onset forms.

MATERIALS AND METHODS: An adult Hispanic female presented with decreased central vision, bilateral pericentral ring scotomas and bull{\textquoteright}s eye-appearing macular lesions at 28 years of age. Her medical history was otherwise unremarkable except for iron deficiency anemia and both urinary tract and kidney infections. Screening of the ABCA4 gene, mutations in which frequently cause bull{\textquoteright}s eye maculopathy, was negative. Subsequently, analysis with whole exome sequencing was performed.

RESULTS: Whole exome sequencing discovered compound heterozygous mutations in MMACHC, c.G482A:p.Arg161Gln and c.270_271insA:p.Arg91Lysfs*14, which segregated with the disease in the family. The genetic diagnosis was confirmed by biochemical laboratory testing, showing highly elevated urine methylmalonic acid/creatinine and homocysteine levels, and suggesting disease management with hydroxycobalamin injections and carnitine supplementation.

CONCLUSIONS: In summary, a unique case of an adult patient with bull{\textquoteright}s eye macular lesions and no clinically relevant systemic symptoms was diagnosed with cblC by genetic screening and follow-up biochemical laboratory tests.

}, keywords = {Adult, Carrier Proteins, Electroretinography, Exome, Female, Genetic Testing, Heterozygote, Homocystinuria, Humans, Macular Degeneration, Mutation, Pedigree, Scotoma, Sequence Analysis, DNA, Tomography, Optical Coherence, Visual Acuity, Visual Fields, Vitamin B 12, Vitamin B 12 Deficiency, Vitamin B Complex}, issn = {1744-5094}, doi = {10.3109/13816810.2015.1010736}, author = {Collison, Frederick T and Xie, Yajing Angela and Gambin, Tomasz and Jhangiani, Shalini and Muzny, Donna and Gibbs, Richard and Lupski, James R and Fishman, Gerald A and Allikmets, Rando} }