Surfactant protein A and D gene polymorphisms and protein expression in victims of sudden infant death.
OBJECTIVE
To investigate the innate immune components surfactant protein A (SP-A) and D (SP-D) in victims of sudden infant death syndrome (SIDS).


METHODS
Ten common single nucleotide polymorphisms (SNPs) in the exons of SP-A1, SP-A2 and SP-D genes were analysed in 42 cases of SIDS and 46 explained sudden infant deaths. SP-A and SP-D protein expression in tissue from the aerodigestive tract was semi-quantitatively evaluated by immunohistochemistry.


RESULTS
SP-D immunoreactivity was found in lungs and tissue from submandibular gland, palatine tonsils and duodenum. Positive SP-A immune staining was found exclusively in lung tissue. Neither the allele nor the haplotype distribution of the SP-A and SP-D genes was significantly different in SIDS compared to explained deaths. The most common SP-A haplotype, 6A2/1A0, tended to be overrepresented in the cases with low immunohistochemical SP-A expression (61%) compared to cases with high expression (49%), p = 0.08. The SP-D expression was not influenced by the 11 C/T or 160 A/G polymorphisms.


CONCLUSIONS
No significant association between the common genetic variants of SP-A and SP-D and SIDS is disclosed by the present study. However, low SP-A protein expression may possibly be determined by the 6A2/1A0 SP-A haplotype, this should be subject for further investigation.
Stray-Pedersen
Arne
A
Institute of Forensic Medicine, University of Oslo, Norway. arne.stray-pedersen@labmed.uio.no
Vege
Ashild
A
Opdal
Siri Hauge
SH
Moberg
Sara
S
Rognum
Torleiv Ole
TO
D005260:Female; D014644:Genetic Variation; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D007231:Infant, Newborn; D016015:Logistic Models; D008297:Male; D020641:Polymorphism, Single Nucleotide; D037662:Pulmonary Surfactant-Associated Protein A / Q000235:genetics*; D037663:Pulmonary Surfactant-Associated Protein D / Q000235:genetics*; D012307:Risk Factors; D013398:Sudden Infant Death / Q000235:genetics*
D037662:Pulmonary Surfactant-Associated Protein A; D037663:Pulmonary Surfactant-Associated Protein D