1/5. Deletion in the OA1 gene in a family with congenital X linked nystagmus.AIMS: To elucidate the molecular genetic defect of X linked congenital nystagmus associated with macular hypoplasia in three white males of a three generation family with clear features of ocular albinism in only one of them. methods: A three generation family with congenital nystagmus following X linked inheritance, and associated with macular hypoplasia was clinically examined (three males and two obligate carriers). Flash VEP was performed to look for albino misrouting. dna samples were subjected to PCR and subsequent analysis using SSCP for all exons of the OA1 gene. RT-PCR was performed on a mRNA preparation from a naevus from one patient. PCR products presenting divergent banding patterns in SSCP and from the RT-PCR were sequenced directly using cycle sequencing with fluorescent chain termination nucleotides and electrophoresis in a capillary sequencer. RESULTS: The index case (patient 1, IV.1) was diagnosed with X linked OA1 at the age of 3 months because of typical clinical features: congenital nystagmus, iris translucency, macular hypoplasia, fundus hypopigmentation, normal pigmentation of skin and hair, and typical carrier signs of OA1 in his mother and maternal grandmother. Pigmentation of the iris and fundus had increased at the last examination at age 4 years. Albino misrouting was present at this age. In the maternal uncle (III.3, 51 years) who also suffered from congenital nystagmus there was clear macular hypoplasia and stromal focal hypopigmentation of the iris but no iris translucency or fundus hypopigmentation. Patient 3 (II.3, 79 years, maternal uncle of patient III.3) had congenital nystagmus and was highly myopic. The fundus appearance was typical for excessive myopia including macular changes. The iris did not show any translucency. Molecular genetic analysis revealed a novel 14 bp deletion of the OA1 gene at nt816 in exon 6. The mutation abolishes four amino acids (Leu 253-Ile-Ile-Cys) and covers the splice site. nucleotides 814/815 are used as a new splice donor thus producing a frame shift in codon 252 and a new stop codon at codon 259. CONCLUSIONS: Macular hypoplasia without clinically detectable hypopigmentation as the only sign of X linked OA1 has been reported occasionally in African-American, Japanese, and white patients. The present family shows absent hypopigmentation in two patients of a white family with a deletion in the OA1 gene. We propose a model of OA1 that allows increase of pigmentation with age. We hypothesise that macular hypoplasia in all forms of albinism depends on the extracellular DOPA level during embryogenesis, and that in OA1 postnatal normalisation of the extracellular DOPA level due to delayed distribution and membrane budding/fusion of melanosomes in melanocytes results in increasing pigmentation.- - - - - - - - - - ranking = 1keywords = hypopigmentation (Clic here for more details about this article) |
2/5. Clinical findings in Japanese patients with waardenburg syndrome type 2.PURPOSE: To determine the visual characteristics of Japanese subjects with the waardenburg syndrome type 2. methods: The visual functions of 11 albino patients who were identified from the screening of 240 children attending a school for children with a hearing deficit were studied. The ophthalmological examinations included eye position, visual acuity, biomicroscopy, ophthalmoscopy, visual field by confrontation or Goldmann's perimetry, stereoacuity by the Titmus test, and color vision by the Ishihara pseudoisochromatic plates. RESULTS: A combination of congenital sensory deafness and partial ocular albinism without lateral displacement of the lacrimal puncta was observed in 11 (4.6%) of the students with hearing deficit. All these children had sectorial heterochromia irides with local retinal hypopigmentation. Lid deformities were not present. The retinal vasculature was normal, and macular hypoplasty was not found. Other than 1 eye with hyperopic amblyopia, no serious visual disturbance was found in these patients. CONCLUSIONS: The 11 students were classified as having waardenburg syndrome type 2. None had a critical visual deficit, and all had partial heterochromia irides and retinal hypopigmentation.- - - - - - - - - - ranking = 0.4keywords = hypopigmentation (Clic here for more details about this article) |
3/5. Congenital Horner's syndrome does not alter Lisch nodule formation.A 21-year-old woman with neurofibromatosis type 1 (NF-1) had a unilateral congenital Horner's syndrome with resultant hypopigmentation of the affected iris. Lisch nodules, which are melanocytic hamartomas, were similar in number, size, and pigmentation in both eyes. The present findings suggest that the formation of Lisch nodules is not influenced by the presence or absence of sympathetic innervation of the iris.- - - - - - - - - - ranking = 0.2keywords = hypopigmentation (Clic here for more details about this article) |
4/5. angelman syndrome.BACKGROUND: Angelman (happy puppet) syndrome is a neuro-developmental condition characterized by an ataxic gait with puppet-like limb movements, paroxysmal bouts of laughter and severe mental retardation. Although considered a rare condition, over 140 cases have been documented since its designation in 1965. To date, only one study has been published investigating the ocular defects of angelman syndrome. methods: In this paper we report the cognitive, motor, systemic, and oculo-visual findings of a 3 year old child with angelman syndrome. RESULTS: The oculo-visual findings include choroidal hypopigmentation, iris hypopigmentation, strabismus, and hyperopia. CONCLUSIONS: As in many neuro-developmental conditions, early diagnosis is crucial. The ocular findings of fundal/iris hypopigmentation and strabismus with minimal refractive error in conjunction with the cognitive, behavioral, and motoric characteristics the patient exhibits may be the first clues for the diagnosis of angelman syndrome in a developmentally delayed child. The initiation of individualized optometric diagnosis and treatment is important for all children with developmental disabilities. The eye care professional should work in concert with speech, occupational, and physical therapists, neurologists, and special educators in the multi-disciplinary treatment and habilitation of all children with disabilities including those with angelman syndrome.- - - - - - - - - - ranking = 0.6keywords = hypopigmentation (Clic here for more details about this article) |
5/5. Clinical and morphological features of waardenburg syndrome type II.Evaluation of 4-month-old girl who presented with congenital cataracts revealed heterochromia iridis, fundus hypopigmentation, residual white forelock and sensory neural hearing loss--findings consistent with waardenburg syndrome type II. Bilateral peripheral iridectomies performed at lensectomy provided tissue for evaluation. light microscopy revealed fewer melanocytes in the blue iris than in the brown. Electron microscopic examination showed a significant (p = 0.0001) reduction in melanosome size in the blue iris, and the nerve endings contained fewer vesicles. A defect in neural crest cell migration and melanin synthesis may be responsible for the heterochromia iridis seen in waardenburg syndrome type II.- - - - - - - - - - ranking = 0.2keywords = hypopigmentation (Clic here for more details about this article) |