This study is a multicenter, non-drug screening study. Enrollment period is 12 months. There are no IMP to be followed or used in the study. Patients who applied to Pediatric Metabolism, Pediatric Neurology and Developmental Pediatrics clinics with the symptoms or findings defined in the protocol as below for 12 months will be included in the study.

Children between the ages of 2 and 6, without hypoxic ischemic encephalopathy, head trauma and developmental brain anomalies, who are admitted to the Pediatric Metabolism, Pediatric Neurology and Developmental Pediatrics clinics with non-specific neurological symptoms such as idiopathic seizures of unknown etiology, speech disorders and motor dysfunctions, will constitute the target population of the study.

Demographic data, medical history and family history of the patients included in the study will be recorded at their first admission. In addition, seizure frequency; cognitive functions, including assessments of language development; physical examination information including assessments of muscle strength, gait, and coordination; Data on neurological evaluation results and visual ability evaluations, such as Electroencephalography (EEG) and Magnetic Resonance Imaging (MRI), will be collected. Following the above screenings, patients between the ages of 2-6 who show at least one of the following: speech disorder with idiopathic seizures/regression in acquired speech skills, symptoms of gait and movement disorders, or photoparoxysmal response to EEG with low-frequency IFS, cerebral atrophy or preventive white matter hyperintensity on MRI, Enzyme analysis and genetic tests will be performed on children to investigate CLN2 disease.The tests are written in detail below.

For Tripeptidyl Peptidase 1 enzyme level measurement, blood will be taken from the patient into a 5 mL EDTA tube at Gazi University Faculty of Medicine, Metabolism Laboratory, and for patients with low enzyme activity, the genetic evaluation test will be performed with whole blood at the Gene2Info Laboratory.

Study endpoints are to determine the frequency of type 2 (CLN2) disease and to determine the demographic and clinical characteristics of these patients with neuronal ceroid lipofuscinosis who showed at least one of the following: speech impairment with idiopathic seizures/decline in acquired speech skills, symptoms of gait and movement disorders, or photoparoxysmal response to EEG with low-frequency IFS, cerebral atrophy or pretricular white matter hyperintensity on MRI.

Inclusion Criteria:

• Girls and boys aged 6 years old

• Having a history of at least one seizure

• With a history of idiopathic seizures;

  • Speech disorder or regression in acquired speaking skills,
  • Motor dysfunctions,
  • Photoparoxysmal response to EEG with low-frequency IFS,
  • Observation of at least one of the symptoms or signs of cerebral atrophy or preventive white matter hyperintensity on MRI

• Without hypoxic ischemic encephalopathy, head trauma and developmental brain anomalies

• Not having been previously diagnosed with CLN2

• The patient and/or his/her legal representative must be willing to sign the written consent form.

Exclusion Criteria:

• Patients younger than 2 years and older than 6 years
• Patients with a known or diagnosed neurodegenerative disorder
• Patients for whom written consent form cannot be obtained from their legal representative

Children between the ages of 2 and 6, without hypoxic ischemic encephalopathy, head trauma and developmental brain anomalies, who are admitted to the Pediatric Metabolism, Pediatric Neurology and Developmental Pediatrics clinics with non-specific neurological symptoms such as idiopathic seizures of unknown etiology, speech disorders and motor dysfunctions, will constitute the target population of the study.