Objective: To search for possible novel mutations in palmitoyl-protein thioesterase 1 (PPT1) gene in two Chinese babies with infantile neuronal ceroid lipofuscinosis (INCL).
Methods: Two probands with INCL, confirmed clinically and pathologically, were used for mutation search in PPT1 gene. Onset of the disease occurred before the age of 1 year and they mainly showed progressive mental and motor retardation. The 9 coding exons and their flanking intron sequences of palmitoyl-protein thioesterase 1 (PPT1) gene were amplified by using PCR and sequenced. The parents of proband 1 were also examined.
Results: One splicing mutation and two missense mutations were identified in the two probands: the proband 1 carrying a compound heterozygous mutation of a IVS1 + 1G-->A mutation in intron 1 and a c550G-->A mutation in exon 6 leading to the amino acid substitution of E184K. Additionally, the parents of the proband 1 also harbored one of the mutations of the patient, respectively. The proband 2 carrying a homozygous mutation of c272A-->C in exon 3, which resulted in the amino acid substitutions of Q91P.
Conclusions: The IVS1 + 1G-->A mutation and Q91P mutation are novel mutations, which lead to INCL. The genetic abnormalities of PPT1 in Chinese patients may not be completely the same as those in the patients of other regions of the world.