Features of KAT6B-related disorders in a patient with 10q22.1q22.3 deletion

ABSTRACT

Background: Blepharophimosis is a fixed reduction in the vertical distance between the upper and lower eyelids with short palpebral fissures. It is a rare facial malformation and is considered an important diagnostic feature in dysmorphic analysis. It is likely that many patients with blepharophimosis-mental retardation syndrome have submicroscopic chromosomal rearrangements, and the use of molecular karyotyping can narrow the known blepharophimosis-mental retardation–critical regions or clarify the effect of the haploinsufficiency of the involved genes on the phenotype.

Materials and methods: A female patient presented with bilateral blepharophimosis, ptosis, epicanthus inversus, telecanthus, low-set and small ears, other minor anomalies, hypotonia and psychomotor developmental delay. Metabolic investigations and array CGH analysis were performed. The results of molecular karyotyping were confirmed by real-time PCR analysis.

Results: Molecular karyotyping revealed a 5.2 Mb deletion in the 10q22.1q22.3 region. Real-time PCR analysis of the proband and her parents confirmed the deletion in the proband and revealed its de novo origin.

Conclusions: With ptosis, hypotonia, and developmental delay as the main diagnostic features of our patient, the effect of histone acetyltransferase-encoding KAT6B gene haploinsufficiency was suspected to have a significant role in determining the phenotype. Detailed clinical characterization of the patient provided additional information on the clinical manifestation of the 10q22 deletion.

KEYWORDS:

• 10q22 deletion
• blepharophimosis
• intellectual disability
• KAT6B gene
• ptosis

Acknowledgment

We are very grateful to the family for their contribution.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.

Funding

This work was funded by the Lithuanian-Swiss cooperation programme to reduce economic and social disparities within the enlarged European Union under project agreement No. CH-3-ŠMM-01/04, UNIGENE project.

Additional information

Funding

This work was funded by the Lithuanian-Swiss cooperation programme to reduce economic and social disparities within the enlarged European Union under project agreement No. CH-3-ŠMM-01/04, UNIGENE project.