Does agenesis or dysgenesis neuroepithelialis retinae, whether or not related to keratoglobus, exist?

Screening for Autism Spectrum Disorder in Children and Adolescents With Leber's Congenital Amaurosis

PURPOSE

To investigate autism spectrum disorder (ASD) indicators in children with Leber congenital amaurosis (LCA).

STUDY DESIGN

Cross-sectional, prospective, and correlational study.

METHODS

Setting: It was conducted at the Institute of Ocular Genetics, the Department of Ophthalmology at Federal University of São Paulo (UNIFESP), and the Autism Spectrum Disorder Laboratory, in São Paulo, Brazil.

PATIENT POPULATION

Participants included patients aged 2 to 16 years with LCA confirmed by genetic testing. There were 20 individuals with ciliopathies (LCA cilio) and 26 with other gene mutations (LCA other). As intervention, the instrument used for ASD screening was the Autism Behavior Checklist (ABC). Marginal descriptive analyses, non-parametric tests, and a linear regression model were conducted. The main outcomes were the scores on the tests correlated with clinical variables.

RESULTS

Of the 46 participants, 6 had ASD scores. There was no statistically significant correlation between the different groups (LCA cilio and LCA other) (p = 0.438). There was no statistically significant correlation between age and ASD (p = 0.308). However, there was a statistically significant correlation between visual acuity and ASD (p = 0.008) and between male gender and ASD (p = 0.025).

CONCLUSIONS

This study suggests that there is no correlation between LCA cilio, LCA other and ASD. These findings bring new insights to the existing literature, which previously lacked robust data on the relationship between LCA and ASD. These data demonstrate that visual acuity plays a crucial role in the development of children with visual impairment as poorer visual acuity is associated with a higher incidence of ASD. Based on this study, early interventions can be designed, especially for individuals without light perception, with the aim of maximizing their developmental outcomes. Furthermore, such data indicates that any improvement in visual acuity outcomes in treatment clinical trials become relevant for child development.

Echoes of William Gowers's concept of abiotrophy

Among William Gowers's many contributions to neurology, the concept of abiotrophy ("an essential failure of vitality") has been relatively overlooked. In this article, we review the echoes of Gowers's concept in neurology, ophthalmology, and aging research. We also argue that abiotrophy is broader than both heredodegeneration and neurodegeneration. Unlike the common view that it simply means premature aging, abiotrophy currently can be understood as a progressive degenerative process of a mature specialized tissue, which is nonsynchronous with normal aging and may affect organs or systems early in life, resulting from the age-dependent effects of genetic mutations or variants, even if environmental factors may also causally contribute to the process. Although the term has largely fallen out of use, there are likely to be everlasting echoes of Gowers's concept, through which he is to be considered a source of the modern thinking about the etiology and nosology of neurological diseases.

Kératoglobe : revue de la littérature

Keratoglobus is a rare bilateral condition characterized by a globular protrusion of the cornea. The cornea remains transparent and shows a generalized thinning, most pronounced in the periphery. Most often keratoglobus is a congenital disease, but it may be secondarily acquired. This corneal pathology causes severe visual impairment: it induces extreme myopia, irregular astigmatism, and corneal scarring due to previous hydrops. Spectacle corrections are utilized as long as they provide adequate visual function. Surgery is performed when visual needs are no longer satisfied. However, surgical management of this disease is difficult because of the extreme thinness of the entire cornea. Penetrating keratoplasty is one of the first surgical approaches to have been tested, but it has been partly renounced in favor of more complex procedures. Optimal surgical treatment for keratoglobus remains unknown because of the scarcity of reported surgical results.

An overview of Leber congenital amaurosis: a model to understand human retinal development

Leber congenital amaurosis is a congenital retinal dystrophy described almost 150 years ago. Today, Leber congenital amaurosis is proving instrumental in our understanding of the molecular events that determine normal and aberrant retinal development. Six genes have been shown to be mutated in Leber congenital amaurosis, and they participate in a wide variety of retinal pathways: retinoid metabolism (RPE65), phototransduction (GUCY2D), photoreceptor outer segment development (CRX), disk morphogenesis (RPGRIP1), zonula adherens formation (CRB1), and cell-cycle progression (AIPL1). Longitudinal studies of visual performance show that most Leber congenital amaurosis patients remain stable, some deteriorate, and rare cases exhibit improvements. Histopathological analyses reveal that most cases have extensive degenerative retinal changes, some have an entirely normal retinal architecture, whereas others have primitive, poorly developed retinas. Animal models of Leber congenital amaurosis have greatly added to understanding the impact of the genetic defects on retinal cell death, and response to rescue. Gene therapy for RPE65 deficient dogs partially restored sight, and provides the first real hope of treatment for this devastating blinding condition.

Leber's congenital amaurosis associated with mitochondrial dysfunction

We report the case histories of two 6-month-old girls, both with young, nonconsanguineous parents, referred to us for suspected blindness. In both cases, Leber's congenital amaurosis was diagnosed. Due to persistently high lactic acid levels in blood, muscle biopsies were taken. Analysis of biopsies revealed that both patients had low levels of complex IV of the mitochondrial respiratory chain; one patient additionally had low levels of complex III. Microscopic and ultrastructural alterations of muscle, typically observed in mitochondrial disorders, were observed only in the second patient. These observations raise the possibility that at least some cases of Leber's congenital amaurosis may be due to alterations in the mitochondrial respiratory chain.

Leber congenital amaurosis and its association with keratoconus and keratoglobus

Leber congenital amaurosis has been associated with keratoconus and it has been postulated that this is due to eye rubbing, the oculo-digital sign, because of poor vision. Six schools for the blind were visited, and 174 children with a visual acuity of less than 3/60 examined. Thirty-five children had Leber amaurosis, and 10 of these had keratoconus (29%) and one had keratoglobus (3%). The six pedigrees of the cases with Leber amaurosis and keratoconus are presented in detail. Only 3 of the 139 other blind children had keratoconus (P < .05) and 1 had keratoglobus. Keratoconus seems specifically associated with Leber amaurosis, probably due to genetic factors, rather than poor visual acuity per se.

Epikeratoplasty for keratoglobus associated with blue sclera

Patients with keratoglobus and blue sclera as part of a generalized connective tissue disorder are at a high risk of developing corneal perforations either spontaneously or after mild trauma. Six patients (6 eyes) between the ages of 2 and 16 years of age (mean, 7.5 years) with keratoglobus, blue sclera, hypermobile joints, and consanguineous parents were treated by epikeratoplasty, using commercially prepared 12.5-mm lenticules. Surgery was performed for tectonic support and/or visual improvement and was successful in five of six patients with a follow-up period of 11 to 27 months (mean, 21 months). One lenticule was removed because the epithelium did not heal. Peripheral interface opacities occurred in three patients.

Bilateral macular colobomas in Leber's congenital amaurosis

Two siblings with Leber's congenital amaurosis had bilateral macular colobomas, nystagmus, extinguished ERGs, and degenerative salt and pepper like changes in the fundus. They had non-recordable or non-meaningful visually evoked cortical potentials in response to both flash and pattern stimuli. The ophthalmic conditions were thought to be inherited as an autosomal recessive trait.

Leber's congenital amaurosis with associated nephronophthisis

The authors present a case of a 15-year-old girl with Leber's congenital amaurosis with associated nephronophthisis. The main findings in this case are: congenital blindness; enophthalmos; photophobia; nystagmus; keratoconus; cataracts; pigmentary degeneration in the fundus of both eyes; progressive uremia with absence of hematuria, proteinuria, pyuria, and glycosuria; low urinary density, normal lipidic profile; osteoporosis; absence of edema; polydipsia; polyuria; and a history of consanguinity between her parents. Tranmission of this entity allows an autosomal recessive pattern.

Leber's congenital amaurosis

An early stage of Leber's congenital amaurosis, characterized by white spots or lines in the fundus, occurred in two children. Light microscopic examination of eyes obtained from one child, a 16-month-old Japanese girl, revealed subretinal deposits corresponding to the white spots and lines in the fundus deposits. Light and electron microscopic examination of the eye showed distinctive changes in the outer retinal layers and choroid, while the inner retinal layers were nearly normal. Characteristic early lesions of congenital amaurosis appeared to be produced by deposits consisting of loose outer segments and apical processes of the pigmental epithelial cell and macrophages. Undifferentiation in the nuclei of the photoreceptor cell, the inner segment, the pigment epithelial cell, and the choriocapillaris were likely characteristics of the early changes of congenital amaurosis.

Congenital Amaurosis of Leber

In two families with congenital amaurosis of Leber, keratoglobus was found in all affected members and posterior subcapsular cataracts in most of them. Consanguinity was present in one family. Pathologic findings in one enucleated eye were presented. The literature on this disease was briefly reviewed. Whether the disease is a definite clinical or genetic entity and whether it might be an agenesis or an abiotrophy, or both, were discussed.