Aim To identify mutations in the SP-B gene of term newborns with RDS.
Patient We studied 6 newborns. RDS developed in a female infant at the first four hours after delivery, who required mechanical ventilation. She was the first child of a non-consanguineous marriage. The family history had no particular remarks. Chest radiography showed a diffuse granular patterm with air bronchograms. Porcine surfactant administration resulted in an evident transient improvement of oxygenation and of the chest radiograph findings. Diagnosis of SP-B deficiency was then considered and genetic analysis was requested. An open lung biopsy was performed after 25 days. The infant died 2 days later.
Methodology Genomic DNA was isolated from parents and patients blood. Synthetic oligonucleotides (18–20 bases), corresponding to intronic sequences for the first 10 exons of the SP-B gene, were used in a PCR amplification. Direct PCR products sequencing was realized in an automated sequencer.
Results No mutations/SNP in the exons from SP-B gene from the 5 out of 6 cases suspected have been found. However, SP-B deficiency was confirmed at 25 days of life in a girl. DNA sequence analysis demonstrated the presence of the 121ins2 mutation in both alleles (homozygous), and in one of them in her parents, accounting for the SP-B deficiency.
Conclusion The molecular genetic study confirmed the diagnosis promptly to evaluate lung transplantation as unique survival treatment option. This is the first report of an SP-B deficient infant from Spain.