TWO CASES WITH DIFFERENT EPILEPSY TYPE AND DYSMORPHIC FEATURES ASSOCIATED WITH 17q21.31 MICRODELETION SYNDROME

Area of Science:

• Genetics
• Neurodevelopmental Disorders

Background:

• 17q21.31 microdeletion syndrome is a genetic disorder associated with intellectual disability, epilepsy, and distinctive facial features.
• The KANSL1 gene has been implicated as a primary genetic cause for this syndrome's characteristic phenotype.

Observation:

• Two Turkish female patients, aged 4 and 14, were diagnosed with 17q21.31 microdeletion syndrome.
• Both patients exhibited varying degrees of intellectual disability, epilepsy, and dysmorphic features; the younger had generalized tonic-clonic seizures, while the older presented with intractable epilepsy and self-mutilation.

Findings:

• Array comparative genomic hybridization (array CGH) revealed a 17q21.31 microdeletion in both patients.
• Case 1 deletion encompassed MAP7, CRHR1, KANSL1, and PLEKHMI genes.
• Case 2 deletion included CRHR1 and PLEKHM genes but notably lacked the KANSL1 gene, representing the first reported instance of a 17q21.31 microdeletion not encompassing KANSL1.

Implications:

• This study expands the understanding of genotype-phenotype correlations in 17q21.31 microdeletion syndrome.
• The findings suggest that genes other than KANSL1 may contribute to phenotypes similar to those observed in 17q21.31 microdeletion syndrome, warranting further investigation into other potential causal genes within the deleted region or elsewhere.