Current State of Clinical and Morphological Features in Human NCL

The neuronal ceroid lipofuscinoses (NCL) are large group of autosomal recessive lysosomal storage disorders with both enzymatic deficiency and structural protein dysfunction. Previously, diagnosis of (NCL) was based on age at onset clinicopathological (C‐P) findings described 4 forms, classified as infantile (INCL) (2), late‐infantile (LINCL) (5), juvenile (JNCL) (6), and adult (ANCL) most patients with NCL have progressive ocular and cerebral dysfunvtion, including cognitive/motor dysfunction and uncontrolled seizures. After reviewing 520 patients with NCL, we found that about 104 (20%) did not fit this classification of NCL With further research, 4 additional forms have been recognized: Finnish (13), Gypsy/Indian (14), Turkish (15)—varoamts of LINCL, and Northern epilepsy (16), also known as progressove epilepsy with mental retaedation. These eight NCL forms resulted from 151 diffeent mutations in genes CLN1 to CLN8 causing different phenotypes (http://www.ucl.ac.uk/nclhttp://www.ucl.ac.uk/ncl). The genes CLN1 and CLN2 encode lysosomal palmitoyl protein diagnosis of NCL is based on clinicopathological (c‐p) findings, enzymatic assay, and molecular genetic testing. Ultrastructural studies must be performed to confirm the presence and nature of lysosomal storage material (fingerprint or curvilinear profiles presence and nature of lysosomal storage or granular osmiophilic deposits) before doing biochemical testing. Pheno/genotypic correlation studies are discussed.