Fundus lesions of adenomatous polyposis.

Congenital hypertrophy of the retinal pigment epithelium (CHRPE) is the most frequent extraintestinal manifestation of familial adenomatous polyposis. Present in 70% of families with familial adenomatous polyposis, CHRPE is a highly reliable and early marker of the disease. Studies over the past 5 years have addressed the histologic characteristics of the pigmented fundus lesions, the definition of universal positive fundus criteria, and mostly the genotype-phenotype correlation. Indeed, the position of the mutation site of the APC (adenomatous polyposis coli) gene on chromosome 5 influences the retinal expressivity because CHRPE is present only if the mutation is located between exons 9 and 15. In CHRPE-positive families, fundus examination is simple, noninvasive, reproducible, inexpensive, and allows early detection of the mutant gene carriers. Knowing the CHRPE status of patients in a family with familial adenomatous polyposis helps to identify constitutional APC mutations. The combination of genetic analysis and fundus examination offers a 100% diagnostic predictability.

Diagnostic value of fundus examination in familial adenomatous polyposis.

BACKGROUND: Multiple, bilateral lesions of congenital hypertrophy of the retinal pigment epithelium (CHRPE) have been described in patients suffering from familial adenomatous polyposis (FAP) since 1980. This study aimed to determine a reliable diagnostic criterion, based on the size and number of retinal CHRPE lesions, allowing the screening of patient carriers of the gene responsible for FAP. METHODS: 32 control subjects and 144 patients belonging to 85 FAP families were studied, divided into 124 carriers of the genetic alteration and 20 non-carriers. RESULTS: In carriers of the deleted gene, multiple, bilateral retinal lesions were consistently observed. Lesion situation, size, shape, and degree of pigmentation were variable however. A positive criterion for FAP was defined as the presence of at least four lesions whatever their size, or at least two lesions one of which is large. This criterion showed a high sensitivity (0.68) and a maximal specificity (1). Within each family, the retinal phenotypic expression was homogeneous. CHRPE lesions were observed in two thirds of the FAP families and absent from the remaining third. CONCLUSION: By using this new positive diagnostic criterion, fundus examination allows early detection of those children carrying the gene responsible for FAP in families positive at ocular examination.

[Ocular involvements in chronic inflammatory diseases in children]. / Atteintes oculaires au cours des maladies inflammatoires chroniques de l'enfant.

Children uveitis represents 2-6% of all cases of uveitis in an ophthalmology clinic. Uveitis can be due to a specific ophthalmic disease or to a systemic disease: juvenile chronic arthritis. Sarcoidosis, Behçet's disease, and connective tissue diseases. Visual function, in these young patients, may be compromised by severe complications such as band keratopathy, posterior synechiae, cataract, glaucoma, and retinal oedema. In some cases, delayed diagnosis and severity of the uveitis are due to its insidious onset, and to the absence of any complaint from the child. Therapeutic approach based on local and general corticoids in complicated cases, must balance the necessity of controlling ocular inflammation and the secondary effects of this treatment in a growing child.

[Uveitis in juvenile chronic arthritis]. / L'uvéite des arthrites chroniques juvéniles.

The authors report the follow-up of thirty patients and 49 eyes, with uveitis associated to juvenile chronic arthritis. Clinical characteristics and risk factors of uveitis are: female gender (90%), bilateral involvement (63%), chronicity (91%), relapses (94%), oligoarticular arthritis (73%), antinuclear antibodies (83%). The intraocular inflammation was most frequently asymptomatic. It is extremely important to screen the patients systematically at regular intervals in order to early diagnose the uveitis to improve the visual prognosis. Risk factors for significant visual loss are still cataract (26.5%) and secondary glaucoma (10%). The most devastating complication is secondary glaucoma.

Restriction of ocular fundus lesions to a specific subgroup of APC mutations in adenomatous polyposis coli patients.

In humans, alteration of the tumor suppressor gene, APC, causes adenomatous polyposis coli, a condition causing predisposition to colorectal cancer. The syndrome inconsistently associates characteristic patches of congenital hypertrophy of the retinal pigment epithelium (CHRPE). Ocular examination revealed that patients expressing CHRPE tend to cluster within specific families. The exact APC mutation was identified in 42 unrelated patients. In all cases these mutations were predicted to lead to the synthesis of a truncated protein. The extent of CHRPE was found to be dependent on the position of the mutation along the coding sequence. CHRPE lesions are almost always absent if the mutation occurs before exon 9, but are systematically present if it occurs after this exon. Thus, the range of phenotypic expression observed among affected patients may result in part from different allelic manifestations of APC mutations.