Abstract

DO.18.03

Genetic causes in congenital Brown syndrome?

Neugebauer A.¹, Fricke J.¹, Strobl J.¹, Schubert R.², Kubisch C.^3
1Zentrum für Augenheilkunde, Universität zu Köln; ²Köln; ³Institut für Humangenetik, Universität zu Köln

Objective: To clarify the etiology of congenital Brown syndrome in regard to the hypothesis that congenital Brown syndrome might be a congenital cranial dysinnervation disorder (CCDD).
Methods: The findings of more than 50 patients with congenital Brown syndrome were analyzed retrospectively with the aim to identify patients with familial Brown syndrome or associated pathological findings. Up to now, three families, each with two cases of Brown syndrome in their history (2 brothers, 2 cousins and twins with “mirror-image” for Brown syndrome) were identified. Furthermore two patients with associated complex congenital disorders. One patient with congenital Brown syndrome had two sisters, twins, with congenital cataracts.
In 4 of these patients a conventional chromosome analysis was performed together with a fluorescence in situ hybridization (FISH) for the long arm of chromosome 22, because a case of Brown syndrome associated with velocardiofacial syndrome and deletion on chromosome 22q11.2 is described.
Further systematic genomwide examinations for microdeletions in patients with complex disorders as well as examinations of functional candidate genes are in preparation.
Results: Conventional chromosomal analysis and the FISH investigation showed normal findings in two patients. In two brothers with congenital Brown syndrome the FISH examination also showed normal findings but a duplication of the band 18p11.1.
Conclusions: A genetic cause of at least some cases of Brown syndrome seems probable because of familial occurrence and because of the association with other malformations. No microdeletion on chromosome 22q11.2 was found in the patients with familial Brown syndrome or accompanying disorders examined by us.

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