[Show abstract][Hide abstract] ABSTRACT: Oculocutaneous albinism (OCA) is a group of genetic disorders characterized by hypopigmentation of the skin, hair, and eyes. Affected individuals experience reduced visual acuity and substantially increased skin cancer risk. There are four major types of OCA (OCA1-OCA4) that result from disruption in production of melanin from tyrosine. Current treatment options for individuals with OCA are limited to attempts to correct visual problems and counseling to promote use of sun protective measures. However, Onojafe et al., reporting in this issue of the JCI, provide hope for a new treatment approach for OCA, as they demonstrate that treating mice that model OCA-1b with nitisinone, which is FDA approved for treating hereditary tyrosinemia type 1, elevates plasma tyrosine levels, and increases eye and hair pigmentation.
The Journal of clinical investigation 09/2011; 121(10):3828-31. · 15.39 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Oculocutaneous albinism (OCA) is caused by mutations in six different genes and their molecular diagnosis encompasses the search for point mutations and intragenic rearrangements. Here we used high resolution array-CGH to search for rearrangements across exons, introns and regulatory sequences of four OCA genes, TYR, OCA2, TYRP1, and SLC45A2. We identified a total of ten new deletions in TYR, OCA2, and SLC45A2. A complex rearrangement of OCA2 was found in two unrelated patients. Whole genome sequencing showed deletion of a 184 kb fragment (identical to a deletion previously found in polish patients), whereby a large portion of the deleted sequence was re-inserted after severe reshuffling into intron 1 of OCA2. The high-resolution CGH array presented here is a powerful tool to detect gene rearrangements. Finally, we review all known deletions of the OCA1-4 genes reported so far in the literature, and show that deletions or duplications account for 5.6% of all mutations identified in the OCA1-4 genes. This article is protected by copyright. All rights reserved.
Pigment Cell & Melanoma Research 09/2013; · 5.84 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Abstract Purpose: To describe and compare ocular findings in patients with Hermansky-Pudlak syndrome (HPS) type 1 and 3. Methods: This is a retrospective case series of 64 patients with HPS from 1999 to 2009 evaluated at an outpatient private ophthalmologic clinic. Patients underwent genetic analysis of selected albinism (Tyrosine and P gene) and HPS genes (HPS-1 and HPS-3) by screening for common mutations and exon sequencing with DNA screening. Descriptive and non-parametric statistical analyses were carried out. Results: Nearly 70% of the patients were homozygous for common Puerto Rican mutations leading to the HPS1 gene (16-BP DUP, 53.6%), while 30% had the 3904-BP DEL HPS3 gene mutation. Best corrected visual acuity (BCVA) was poorer in patients with type 1 HPS than in patients with type 3 HPS (p < 0.001), esotropia was more common among type 1 HPS patients (p < 0.018), while exotropia was more common among patients with type 3 HPS. Total iris transillumination was more common in patients with type 1 HPS and minimal iris transillumination in patients with type 3 HPS (p < 0.001). The maculae were translucent in patients with type 1 HPS, while patients with type 3 HPS had opaque maculae (p < 0.001). Conclusions: Patients with type 1 HPS had poorer BCVA, increased incidence of esotropia, lighter iris and macular appearance. In contrast, patients with type 3 HPS had more exotropia. In addition, to our knowledge this is the largest series type 3 HPS ever reported.
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