Paediatria Croatica - Progressive myoclonic seizures in siblings with neuronal ceroid lipofuscinosis

Progressive myoclonic seizures in siblings with neuronal ceroid lipofuscinosis

Neuronal ceroid lipofuscinoses (NCLs) are progressive autosomal recessive disorders belonging to the group of lisosomal-storage disorders. The main mechanism of these lethal diseases is the excessive accumulation of lipofuscin in the central nervous system, but other organs are also affected. The prevalence of NCLs ranges from 0.36 to 0.46/100 000. Based on the age of onset, NCLs are divided into four types: infantile, late-infantile, juvenile and adult neuronal ceroid-lipofuscinosis. Late-infantile neuronal ceroid lipofuscinosis (LINCL) appears at 2-4 years of age, with myoclonic seizures as the common inital sign. With the progress of the disease other neurological signs and mental deterioration appear. The diagnosis is based on deficiency of enzyme tripeptidyl-peptidase 1 (TPP-1) activity in leukocytes and CLN2 gene mutation. There is no causal treatment for the disease and a lethal outcome is expected after 8-12 years. Here we present the diagnosis and course of LINCL in two siblings, whose parents are unaffected heterozygotes and are not related. The first signs of the disease were myoclonic seizures resistant to medication at the age of 1.5 and 2, years respectively. With the course of the disease, seizures were followed by other neurological symptoms, mental deterioration, impairment of sight and delayed general development. The older sibling is now 5 years of age, is at an advanced stage of the disease and is in a poor physical state, paralysed, with occasional myoclonic seizures, not able to talk, has a pronounced tremor, involuntary movements and cerebellar ataxia. The younger sibling is now 3.5 years of age, he is still mobile, but the first signs of mental and motoric deterioration can be noted. The predominant signs are frequent myoclonic and atonyc seizures, up to 40 per day, which are resistant to all antiepileptic medications. The parents, whose third child is unaffected, have been offered psychological and social help.