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Journal: Ophthalmic genetics

154

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’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’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’s eye macular lesions and no clinically relevant systemic symptoms was diagnosed with cblC by genetic screening and follow-up biochemical laboratory tests.

Concepts: Genetics, Anemia, Folic acid, Vitamin B12, Iron deficiency anemia, Genetic disorders, Methylmalonic acid, Methylmalonic acidemia

25

Neurofibromatosis type 1 (NF-1) is an autsomal dominant disorder which can occasionally result from somatic mosaicism and manifest as segmental forms of the disease.

Concepts: Neurofibromatosis type I, Café au lait spot

24

To evaluate the benefits of phacoemulsification and intraocular lens implantation in patients with oculocutaneous albinism (OCA).

Concepts: Lens, Intraocular lens, Albinism, Oculocutaneous albinism

24

Insulin-like growth factor 1 (IGF1) and insulin-like growth factor 1 receptor (IGF1R) have been shown to influence the development of form-deprivation myopia. However, genetic association between these two genes and high myopia remains inconsistent in different studies. This study was conducted to investigate the association between IGF1and IGF1R and high myopia in a Han Chinese population.

Concepts: Gene, Genetics, Gene expression, Biology, Insulin-like growth factor 1, Han Chinese, People's Republic of China, Insulin-like growth factor

0

Biallelic mutations in the gene SLC4A4 (Solute Carrier Family 4 Member 4) cause protean manifestations in children that include proximal retinal tubular acidosis, developmental delay, band keratopathy, and glaucoma. A unique SLC4A4 mutation causes an ocular-only phenotype. In this retrospective case series, we highlight our experience with children referred to a pediatric ophthalmologist who were found to harbor underlying biallelic SLC4A4 mutations.

Concepts: DNA, Natural selection, Evolution, DNA repair, Ophthalmology, Point mutation, Solute carrier family, SLC4A4

0

To present the clinical and cytogenetic features of a previously unreported family with posterior amorphous corneal dystrophy (PACD) associated with a heterozygous deletion of the small leucine-rich proteoglycan (SRLP) genes on chromosome 12.

Concepts: DNA, Gene, Genetics, Species, Chromosome, Proteoglycan, Cytogenetics, Proteoglycans

0

To evaluate the expansion of the hyperautofluorescent ring and the retinal structure changes over time in cone-rod dystrophy (CRD) patients, using fundus autofluorescence (FAF) and spectral-domain optical coherence tomography (SD-OCT).

Concepts: Optics, Medical imaging, Retina, Ophthalmology, Tomography

0

To describe early structural and functional retinal changes in a patient with Cohen syndrome.

Concepts: Retinal

0

It is known that PRPH2 variants appear to be rare causes of retinitis pigmentosa (RP) in the Japanese population. The purpose of this study was to describe clinical and genetic features in autosomal dominant RP (adRP) patients with a novel disease-causing variant in the PRHP2 gene.

Concepts: Genetics, Biology, Retinitis pigmentosa, Variant type

0

The constellation of signs including microcephaly, retinal colobomas, and exudative vitreo-retinopathy suggests a mutation of the KIF-11 gene on chromosome 10q. We report a female infant with these features but due, instead, to a contiguous gene deletion on chromosome Xp including the OMIM morbid genes CASK, KDM6A, NDP, MAOA, NYX, and DDX3X. The NDP deletion could account for the exudative retinopathy and the CASK deletion for the microcephaly, while CASK and KDM6A have both been associated with coloboma. This case highlights genetic heterogeneity for the clustering of these signs.

Concepts: DNA, Gene, Genetics, Cell, Bacteria, Evolution, Chromosome, Deletion