An emerging 1q21.1 deletion-associated neurodevelopmental phenotype.
In this study, we describe the neurodevelopmental and epileptic phenotypes in a family with an inherited 1q21.1 deletion. During the pregnancy with the proband, increased nuchal translucency and oligohydramnion were detected. The proband showed mild global developmental delay and ataxic gait. Seizures started in the proband at the age of 2 years and manifested as generalized tonic-clonic seizures, atypical absence seizures, head drops, and drop attacks with no abnormal findings on interictal electroencephalogram. We performed an Agilent Human Genome CGH (comparative genomic hybridization) Microarray 105A, and a microdeletion on chromosome 1q21.1 was identified in both the patient and his asymptomatic father. This deletion encompasses 1.65 Mb and is larger than the reported recurrent class I deletions in this region. Cryptic cytogenetic abnormalities should be considered in patients with neurodevelopmental problems and atypical presentation of epilepsy with a normal electroencephalography (EEG).