122 Fig. 2 a, b Striatum. SCMAS staining showing advanced stor- age conWned to the population of small and middle-sized neurons. Large neurons display border- line storage only. Insert in a shows intensive storage in the large neuron in typical CLN2 (bars 30 m). c, d Medulla oblongata neurons, SCMAS staining. Variable storage inten- sity ranging from the borderline to high level (bars 30 m). e, f Spinal medulla, SCMAS stain- ing. Motoneurons with border- line storage, contrasting with pronounced storage in posterior columns neurons (bars 30 m). Insert in a shows intense storage in motoneurons in classical CLN2 (bar 100 m) Acta Neuropathol (2008) 116:119–124 much less storage in the presented case. The storage lyso- somes contained curvilinear proWles. Occasionally, there was typical lipofuscin in separate lysosomal populations (hepatocytes, renal tubules). TPP1 activities in both parents and sister showed typical heterozygote values: mother 129, father 138, sister 171 nmol mg prot ¡1 h¡1 (controls: 202–482 (mean § SD 297 § 70, n = 43)). Direct sequencing revealed that the proband’s father and sister are carriers of frequent mutation c.622C > T (p.Arg208X) in the 6th exon of the CLN2 gene. In the maternal gene a novel variation c.1439T > G in exon 12 was found. Its predicted eVect on protein structure is an amino acid exchange of a valine for a glycine residue at position 480 (p.Val480Gly). Sequencing of the transcript (cDNA) showed the heterozygous substitution c.1439T > G but did not reveal any eVect of this transversion on mRNA splicing. Restriction analysis, using endonucleases BsrI or ScrFI (NEB, Ipswich, MA, USA) conWrmed the substitu- 123 tion c.1439T > G in the mother’s gene and was negative in 300 control alleles. This result together with high phyloge- netic conservation of valine residue in CLN2 gene, in 10 species, supports our consideration, that this missense nucleotide change is causative. Thus the sequence variations c.622C > T (p.Arg208X) and c.1439T > G (p.Val480Gly) conWrm the diagnosis of cLINCL. Discussion Cases of CLN2 with atypical clinical manifestation are extremely rare. So far only seven patients (in Wve families) have been published [11, 19, 25]. Their clinical course con- sisted of progressive loss of motor functions (extrapyrami- dal and cerebellar signs), dementia, and in some of them uncontrollable seizures; visual impairment was variable. Formally the course corresponded to the juvenile pheno- type. Dominant ultrastructure was curvilinear, but an