SMN1 and NAIP genes deletions in different types of spinal muscular atrophy in Khuzestan province, Iran

Spinal muscular atrophy [SMA] is the second most common lethal autosomal recessive disease. It is a neuromuscular disorder caused by degenerative of lower motor neurons and occasionally bulbar neurons leading to progressive limb paralysis and muscular atrophy. The SMN1 gene is recognized as a SMA causing gene while NAIP has been characterized as a modifying factor for the clinical severity and age at disease onset in SMA patients [SMA subtypes]. The relationship between NAIP deletion and type of SMA remains to be clarified; we investigated this gene alteration in all types of SMA patients. Molecular analysis was performed on fifty patients with a clinical diagnosis of SMA in Khuzestan province. In addition to common PCR-RFLP analysis for exon 7 and 8 of SMN1 gene, as an internal control we analysed NAIP deletion with PCR of exon 5 of this gene in a multiplex PCR with exon 13 of it. Homozygous-deletion frequency rate for the telomeric copy of SMN [SMN1] exon 7 in all types [type I, II, III] of SMA was approximately 90% and the frequency of deletion in exon 7 and 8 together in all types estimated about 70%. Moreover NAIP gene was deleted in about 60% of these patients and this shows deletion in 91% of type I SMA patients. The correlation between NAIP-deletion and SMN1 mutation showed a high frequency rate. In this study, high frequency of NAIP gene deletion in all type of disease shows the importance role of it in disease pathogenesis. High frequency of NAIP deletion in SMA type I, also shows the importance of the gene in type and severity of disease so it may be a modifier factor in severity of disease

Neuronal Apoptosis Inhibitory Protein is Overexpressed in Patients with Unfavorable Prognostic Factors in Breast Cancer

Neuronal apoptosis inhibitory protein (NAIP) is a recently identified inhibitor of apoptosis protein. However, the clinical relevance of NAIP expression is not completely understood. In an attempt to determine the clinical relevance of NAIP expression in breast cancer, the levels of NAIP and survivin expression were measured in 117 breast cancer samples and 10 normal breast tissues using quantitative reversetranscriptase-polymerase chain reaction. While there was no evidence of NAIP expression in the normal breast tissue, NAIP was expressed in all breast cancer samples. The level of NAIP expression in breast cancer was significantly higher (257 times) than in the universal tumor control. There was a strong correlation between the level of NAIP expression and the level of survivin expression (p=0.001). The level of NAIP expression in patients with a large tumor (> or =T2) and patients with an unfavorable histology (nuclear grade III) was significantly higher than in those patients with a small tumor (T1) and patients with a favorable histology (nuclear grade I, II) (p=0.026 and p=0.050, respectively). Although the level of NAIP expression was higher in patients with other unfavorable prognostic factors, it was not significant. The three-year relapse-free survival rate was not significantly the patients showing high NAIP expression and patients showing low NAIP expression (86.47+/-4.79% vs. 78.74+/-6.57%). Further studies should include the expressions of NAIP in a larger number of patients and for a longer period of follow-up to evaluate correlation with metastasis and treatment outcome. In conclusion, NAIP is overexpressed in breast cancer patients with unfavorable clinical features such as stage and tumor size, suggesting that NAIP would play a role in the disease manifestation.

Correlation between deletion patterns of SMN and NAIP genes and the clinical features of spinal muscular atrophy in Indian patients.

BACKGROUND: Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder involving degeneration of anterior horn cells of spinal cord resulting in progressive muscle weakness and atrophy. AIMS: The molecular analysis of two marker genes for spinal muscular atrophy (SMA) i.e, the survival motor neuron gene (SMN) and the neuronal apoptosis inhibitory protein gene (NAIP) was conducted in 39 Indian patients with clinical symptoms of SMA. Out of these, 28 showed homozygous deletions and the phenotypic features of these SMA patients were compared with the corresponding genotypes. SETTINGS: A tertiary care teaching Hospital. DESIGN: This is a prospective hospital based study. MATERIALS AND METHODS: Polymerase chain reaction (PCR) combined with restriction fragment length polymorphism (RFLP) was used to detect the deletion of exon 7 and exon 8 of SMN1 gene, as well as multiplex PCR for exon 5 and 13 of NAIP gene. RESULTS: Exons 7 and 8 of SMN and NAIP (exon 5) were homozygously deleted in 73% of SMA I and 27% of SMA II patients. SMN exon 7 and 8 deletions without NAIP deletions were seen in 27% of type I SMA and 46% of SMA type II patients. Two patients of type III SMA showed single deletion of SMN exon 7 along with 27% of SMA type II patients. CONCLUSION: With the advent of molecular biology techniques, SMN gene deletion studies have become the first line of investigation for confirmation of a clinical diagnosis of SMA. The findings of homozygous deletions of exons 7 and/or 8 of SMN1 gene confirms the diagnosis of SMA, even in patients with atypical clinical features. Deletions of NAIP gene were mainly seen in severely affected patients, hence is useful for predicting the prognosis.