Late infantile neuronal ceroid lipofuscinosis: mutations in the CLN2 gene and clinical course in Spanish patients

Late infantile neuronal ceroid lipofuscinosis (Jansky-Bielchowsky disease) is a rare disease caused by mutations in the CLN2 gene. The authors report the clinical outcome and correlate with genotype in 12 Spanish patients with this disease. Psychomotor regression, epilepsy, and other clinical symptoms/signs were assessed. Age at onset of clinical symptoms ranged from 18 months to 3.7 years, and they included delayed speech and simple febrile seizures followed by epilepsy. Partial seizures and myoclonic jerks occurred at an earlier age (median 3.4 and 3.7 years, respectively) than ataxia and cognitive decline (median 4 years). Clinical regression was initiated by loss of sentences (median 3.7 years) followed by loss of walking ability and absence of language (median 4.5 years). Patients showed blindness and lost sitting ability at similar age (median 5 years). The authors report 4 novel mutations in the CLN2 gene. This study provides detailed information about the natural history of this disease.

Infantile neuronal ceroid lipofuscinosis: follow-up on a Spanish series

Infantile neuronal ceroid lipofuscinosis (INCL; NCL1, Haltia-Santavuori disease) is caused by mutations in the CLN1/PPT gene which are associated with an early onset INCL phenotype. The most detailed descriptions of INCL have come from Finland and a few series have been reported from southern European countries. Clinical course and follow-up of six Spanish patients with INCL are reported with the aim of assessing the chronological evolution and severity of this disease. The age at disease onset ranged from 8 to 15 months. Delayed motor skills were the initial symptom when the disease began before 12 months of age, and ataxia was the first sign when the disease began later. Cognitive decline, which is described between 12 and 18 months of age, occurred from 16 to 20 months of age. In our series early stage is characterized by motor impairment, cognitive decline and autistic features. Visual failure may appear simultaneously with the neurological symptoms, leading quickly to blindness. As reported, psychomotor regression appeared between 2 and 3 years of age. Myoclonic jerks occurred after 24 months of age and epilepsy was the last symptom of the disease. We report two novel mutations in a patient without epilepsy to date and describe the features of two siblings homozygous for the V181M (c.541G>A) mutation, associated with the most severe INCL phenotype. The clinical evolution might be helpful to identify patients affected by this rare disease. Early diagnosis is essential in order to provide genetic counselling to affected families. Our series may contribute to the study of the genotype-phenotype INCL correlation in the Mediterranean countries.

Juvenile neuronal ceroid lipofuscinosis: clinical course and genetic studies in Spanish patients

BACKGROUND

Juvenile neuronal ceroid lipofuscinosis (JNCL, NCL3, Batten disease) is usually caused by a 1.02-kb deletion in the CLN3 gene. Mutations in the CLN1 gene may be associated with a variant form of JNCL (vJNCL). We report the clinical course and molecular studies in 24 patients with JNCL collected from 1975 to 2010 with the aim of assessing the natural history of the disorder and phenotype/genotype correlations.

PATIENTS AND METHODS

Patients were classified into the groups of vJNCL with mutations in the CLN1 gene and/or granular osmiophilic deposit (GROD) inclusion bodies (n = 11) and classic JNCL (cJNCL) with mutations in the CLN3 gene and/or fingerprint (FP) profiles (n = 13). Psychomotor impairment included regression of acquired skills, cognitive decline, and clinical manifestations of the disease. We used Kaplan-Meier analyses to estimate the age of onset of psychomotor impairment.

RESULTS

Patients with vJNCL showed learning delay at an earlier age (median 4 years, 95% confidence interval [CI] 3.1-4.8) than those in the cJNCL group (median 8 years, 95% CI 6.2-9.7) (P = 0.001) and regression of acquired skills at a younger age. Patients with vJNCL showed a more severe and progressive clinical course than those with cJNCL. There may be a Gypsy ancestry for V181L missense mutation in the CLN1 gene.

CONCLUSIONS

The rate of disease progression may be useful to diagnose vJNCL or cJNCL, which should be confirmed by molecular studies in CLN1/CLN3 genes. Further studies of genotype/phenotype correlation will be helpful for understanding the pathogenesis of this disease.