Neurological manifestations in Patau syndrome

Patau syndrome (Trisomy 13) is a chromosomal abnormality due to the presence of an extra chromosome 13. It is a polymalformative syndrome characterized by the association of several cerebral malformations such as holoprosencephaly, facial dysmorphy, ocular anomalies, postaxial polydactyly, visceral malformations and a very severe psychomotor delay. This work aims to highlight the neurological problems associated with Patau syndrome. We report the case of an 8-month-old female infant. She presents ocular cataract, posterior cleft palate and post axial polydactyly. Abdominal ultrasound and CT scan were normal. The orbital ultrasonography showed bilateral congenital cataract and bilateral temporal cristalo-postoral vitreous band. The electroencephalogram (EEG) showed a total disorganization of the background activity with a chaotic, anarchic aspect, replaced by diffuse, bilateral, synchronous discharges of hypsarrhythmic type and the Doppler echocardiography showed an AIC ostium secundum of 6 mm. The constitutional karyotype showed a free and homogeneous trisomy 13 (47,XX,+13).  Patau syndrome is defined by a triad: microphthalmia/anophthalmia, cleft lip and palate, and postaxial polydactyly. Confirmation is obtained by cytogenetic testing. The malformations affect midline development including the nervous system such as corpus callosum anomalies, ventriculomegaly, neural tube defects, hydrocephalus, holoprosencephaly, cerebellar dysplasia, olfactory aplasia, and cortical dysplasia. The neurological presentation is severe: hypotonia, hyporeactivity and epilepsy. Nonspecific EEGs have been reported, including diffuse epileptic discharges, focal slowing, spike-wave/polypoint-wave complexes and a predominant theta rhythm. Patients with Patau syndrome may have brain malformations with an increased risk of seizures and variable treatment response. The genetic counseling is important to assist family members. Keywords: Trisomy 13, Patau syndrome, cerebral malformations, hypsarrhythmia, seizures.