Two Siblings with Kaufman Oculocerebrofacial Syndrome Resembling Oculoauriculovertebral Spectrum

Abstract

Kaufman oculocerebrofacial syndrome is a rare autosomal recessive disorder which represents a phenotype mainly involving craniofacial and neurodevelopmental manifestations due to UBE3B gene mutations. The vast majority of the affected individuals exhibit microcephaly, eye abnormalities, and typical facial gestalt including blepharophimosis, ptosis, telecanthus, upslanting palpebral fissures, dysplastic ears, and micrognathia. We encountered 2 siblings in whom severe psychomotor delay, distinctive facial features, hearing loss, and respiratory distress were observed. Some clinical manifestations of the patients, including epibulbar dermoid, microtia, and multiple preauricular tags, were reminiscent of the oculoauriculovertebral spectrum. However, 2 affected siblings exhibited a similar clinical picture consisting of microcephaly, severe developmental and cognitive disabilities, failure to thrive, and dysmorphic features, which were not fully consistent with oculoauriculovertebral spectrum. Also, hypoplastic nails, considered as a core manifestation of Coffin-Siris syndrome, were present in our patients. Therefore, whole-exome sequencing was carried out in order to identify the underlying genetic alterations, contributing to the complex phenotype shared by the 2 siblings. A homozygous pathogenic mutation was found in both affected siblings in the UBE3B gene which caused Kaufman oculocerebrofacial syndrome. Kaufman oculocerebrofacial syndrome should be considered among the autosomal recessive causes of blepharophimosis-mental retardation syndromes, particularly in populations with a high rate of consanguineous marriages, even if there are dysmorphic facial features that are not typically associated with the phenotype.

Keywords: Blepharophimosis-mental retardation syndromes; Intellectual disability; Kaufman oculocerebrofacial syndrome; Oculoauriculovertebral spectrum; UBE3B.