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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

A child with bilateral familial retinoblastoma underwent staging MRI brain and orbit which identified subtle leptomeningeal enhancement, thus prompting an MRI whole body, which revealed a retroperitoneal mass, confirmed on laparoscopic biopsy to be neuroblastoma. This is the first reported case of these two rare embryonal non-central nervous system tumors occurring concurrently. The cause of this concurrence is unknown despite their pathogenic similarities with a chance of 4 cases per 10 billion children aged 1-4 years. Incidental neuroblastomas in infants can regress spontaneously but this child underwent systemic chemotherapy for his retinoblastoma that may have caused regression of the neuroblastoma.

Concepts: Central nervous system, Nervous system, Cancer, Brain, Oncology, Brain tumor, Skull, Retinoblastoma

0

Marfan syndrome (MFS) is a genetic disorder that affects multiple organ systems, including the eye. The most common ocular manifestations include ectopia lentis and retinal detachment. The current literature qualitatively cites that MFS patients have miotic or “poorly dilating” pupils. This study was the first to quantitatively assess pupillary function in MFS patients.

Concepts: Genetic disorder, Eye, Ophthalmology, Marfan syndrome, Pupil, Ectopia lentis, Mydriasis, Miosis

0

Möbius syndrome is a rare congenital condition which presents not merely with 6th and 7th nerve palsies, but involves gaze paresis associated with craniofacial, limb, and other abnormalities. Heterogeneity is well known in patients with Möbius syndrome and rather than being of familial inheritance based on rare cases, it is much more recognized as a sporadic syndrome. We report an infant with features of congenital Möbius syndrome associated with cardiac rhabdomyomas in the absence of tuberous sclerosis.

Concepts: Congenital disorder, Tuberous sclerosis, In the Absence of Truth, Rhabdomyoma

0

A 4-year-old female with a unilateral circumscribed choroidal hemangioma and secondary total exudative retinal detachment. A nasal skin scar-like lesion incised to confirm a histopathologic diagnosis of linear nevus sebaceous. Further imaging disclosed asymmetry of the lateral ventricle frontal horns, suggestive of the diagnosis of linear nevus sebaceous syndrome. The choroidal hemangioma was treated with I-125 episcleral brachytherapy (apical dose of 45 Gy). At 6 months post-radiation, the tumor showed regression with total resolution of exudative retinal detachment.

Concepts: Anatomical pathology

0

Achromatopsia is an autosomal recessive condition, characterised by reduced visual acuity, impaired colour vision, photophobia and nystagmus. The symptoms can be profoundly disabling, and there is no cure currently available. However, the recent development of gene-based interventions may lead to improved outcomes in the future. This article aims to provide a comprehensive review of the clinical features of the condition, its genetic basis and the underlying pathogenesis. We also explore the insights derived from animal models, including the implications for gene supplementation approaches. Finally, we discuss current human gene therapy trials.

Concepts: Gene, Genetics, Allele, Molecular biology, Biology, Virus, Color blindness, Gene therapy

0

Recent genome-wide association studies reported strong association of genetic variation at the CDKN2B/CDKN2B-AS1 locus on 9p21 with normal-tension glaucoma (NTG) in multiple populations. The mechanism by which this locus causes disease remains to be elucidated. We investigated the association of DNA methylation of CpG islands at this locus with NTG.

Concepts: DNA, Gene, Genetics, Gene expression, Restriction enzyme, Histone, Biology, DNA methylation