Neonatal buccal cell collection for DNA analysis

Genomics in premature infants: a non-invasive strategy to obtain high-quality DNA

We used a cost-effective, non-invasive method to obtain high-quality DNA from buccal epithelial-cells (BEC) of premature infants for genomic analysis. DNAs from BEC were obtained from premature infants with gestational age ≤ 36 weeks. Short terminal repeats (STRs) were performed simultaneously on DNA obtained from the buccal swabs and blood from the same patient. The STR profiles demonstrated that the samples originated from the same individual and exclude any contamination by external DNAs. Whole exome sequencing was performed on DNAs obtained from BEC on premature infants with and without necrotizing enterocolitis, and successfully provided a total number of reads and variants corroborating with those obtained from healthy blood donors. We provide a proof of concept that BEC is a reliable and preferable source of DNA for high-throughput sequencing in premature infants.

Cost-effective analysis of genotyping using oral cells in the geriatric population

We evaluated the cost-effectiveness of using buccal swab brushes in comparison with blood samples for obtaining DNA for large epidemiological studies of the elderly population. The data reported here are from the third phase of the Integral Study of Depression among the Elderly in Mexico City's Mexican Institute of Social Security, conducted in 2007. The total cost of the two procedures was determined. The measurement of effectiveness was the quality and quantity of DNA measured in ng/μL and the use of this DNA for the determination of apolipoprotein E (APO E) polymorphism by PCR. Similar rates of amplification were obtained with the two techniques. The cost of the buccal swab brushes, including sample collection and DNA extraction, was US$16.63, compared to the cost per blood sample of US$23.35. Using the buccal swab, the savings was US$6.72 per patient (P < 0.05). The effectiveness was similar. Quantity and quality of DNA obtained were similar for the oral and blood procedures, demonstrating that the swab brush technique offers a feasible alternative for large-scale epidemiological studies.

The use of buccal cells for rapid diagnosis of myotonic dystrophy type 1

Type 1 myotonic dystrophy (DM1) is an autosomal dominant disorder caused by a CTG repeat expansion. RNA containing expanded CUG repeats does not leave the nucleus, but accumulates in discrete nuclear foci which sequester the human muscleblind-like (MBNL) proteins. We have examined buccal cells from 15 adult DM1 patients and 7 control non-DM patients to determine whether nuclear foci can be detected by either immunostaining for MBNL1 protein or fluorescent in situ hybridisation (FISH) for the CUG repeat RNA. Both methods detected nuclear foci in all three early-onset patients, but only in a minority of 12 less severe DM1 patients. There were no false-positive results in the 7 controls. Although the method does not reliably identify all DM1 patients, it may prove useful as a rapid test for severe congenital DM1 in floppy babies.