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Two genes, i.e. survival motor neuron (SMN) and neuronal apoptosis inhibitory protein (NAIP) have been mapped to the SMA region of chromosome 5q13. Both genes are frequently deleted or truncated in SMA patients. We have studied 26 patients with SMA types I-III, 29 first relatives, and 14 subjects with mild adult-onset type IV. DNA deletion genotypes were determined by PCR techniques amplifying exons 7 and 8 of SMN, and exon 5 of NAIP gene which distinguish SMN and NAIP telomeric copy from a non-pathogenic gene homologue as a centromeric copy. Results revealed the homozygous deletions of exon 7 and 8 of the SMN gene and exon 5 of the NAIP gene in 3/3 infants with SMA I and in 1/20 with SMA type II. Exons 7 and 8 of the SMN gene were homozygously deleted in 10/20 and only exon 7 in 6/20 children with SMA type II. The overall percentage of deletion cases observed was 77% in children with SMA types I-III. Adult patients with type IV SMA showed no homozygous deletion of exons 7, 8 and 5 of the SMN and NAIP genes. Also, all relatives had both a telomeric and centromeric SMN and NAIP copy. Deletion analysis of SMN and NAIP genes are a significant diagnostic tool, because there are clinical entities resembling SMA which most likely have another pathogenetic background.

Mutations in the LDL-receptor gene cause a marked elevation of plasma cholesterol, in particular of the LDL subfraction, and the clinical phenotype of familial hypercholesterolemia. Mutation analysis was performed in 127 hypercholesterolemic patients from Zagreb. The promoter region and all 18 exons of the LDL-receptor gene were screened using single-strand conformation polymorphism method. The molecular defects detected were then characterized by direct sequencing. Nucleotide changes were detected in 9.4% patients with hypercholesterolemia. About five different mutations in the low-density lipoprotein receptor gene were identified in 12 patients. Four missense mutations (C6W, C127R, D200G and S265T) were located in ligand binding domain and one (G457R) was located in the epidermal growth factor precursor homology domain. One of these mutations, C127R (FH Zagreb), has not been described before in any other population. Five genetic polymorphisms (C6C, A370T, R450R, N570N and V632V) were detected in other. Knowledge of genetic basis of hypercholesterolemia may contribute to designing a specific diagnostic analysis scheme. Therefore, for molecular diagnosis of familial hypercholesterolemia in Croatia, the whole low density lipoprotein receptor gene of each patient must be screened for new and recurrent mutations.

Fractures of denture base polymer material are one of the most frequent reasons for repair of removable dentures. The aim of this study was to determine the influence of depth alignment of glass fiber reinforcements onto denture base polymer flexural obtained with the “short beam” testing method. The study showed higher values of flexural strength when reinforcements were placed 1mm from specimen surface (130,63 to 158,55MPa) compared to 0,5mm distance from specimen surface (117,83 to 153,68MPa). Specimens tested after polymerization had higher flexural strength values than specimens tested after storage in water, while thermocycled specimens unexpectedly revealed the highest values. It could be concluded that fiber reinforcements should be positioned more than 0,5mm (up to 1mm) from the base surface of dental prostheses since lesser distance would diminish the reinforcing effect.