Stability of genomic DNA in dried blood spots stored on filter paper.

The stability of DNA in dried blood samples obtained from the neonatal screening program in Thailand was retrospectively studied in order to determine the conditions necessary for the long term storage of samples for DNA banking. Specimens from 1991 to 2001, which had been kept in the ambient conditions at the Department of Medical Science, Ministry of Public Health, Thailand, were randomly sampled and used for the study. Genomic DNA was extracted from the samples and DNA fragments of the PAX8 and beta-globin genes were amplified by PCR to determine DNA stability. The study showed that 255-bp and 674-bp fragments of the PAX8 gene could be amplified from all the samples. The DNA fragment of 1,039 bp of the beta-globin gene could be detected in all of the samples for the years 1993 to 2001, but only in seven and five out of the ten studied samples for each of the years 1991 and 1992, respectively. Our study shows that genomic DNA is stable in dried blood stored on filter paper at ambient tropical conditions for at least 11 years. However, DNA quality for amplification of larger DNA fragments decreased when the specimens were stored for longer than 10 years.

An Economic Evaluation of Neonatal Screening for Inborn Errors of Metabolism Using Tandem Mass Spectrometry in Thailand.

BACKGROUND: Inborn errors of metabolism (IEM) are a rare group of genetic diseases which can lead to several serious long-term complications in newborns. In order to address these issues as early as possible, a process called tandem mass spectrometry (MS/MS) can be used as it allows for rapid and simultaneous detection of the diseases. This analysis was performed to determine whether newborn screening by MS/MS is cost-effective in Thailand. METHOD: A cost-utility analysis comprising a decision-tree and Markov model was used to estimate the cost in Thai baht (THB) and health outcomes in life-years (LYs) and quality-adjusted life year (QALYs) presented as an incremental cost-effectiveness ratio (ICER). The results were also adjusted to international dollars (I$) using purchasing power parities (PPP) (1 I$ = 17.79 THB for the year 2013). The comparisons were between 1) an expanded neonatal screening programme using MS/MS screening for six prioritised diseases: phenylketonuria (PKU); isovaleric acidemia (IVA); methylmalonic acidemia (MMA); propionic acidemia (PA); maple syrup urine disease (MSUD); and multiple carboxylase deficiency (MCD); and 2) the current practice that is existing PKU screening. A comparison of the outcome and cost of treatment before and after clinical presentations were also analysed to illustrate the potential benefit of early treatment for affected children. A budget impact analysis was conducted to illustrate the cost of implementing the programme for 10 years. RESULTS: The ICER of neonatal screening using MS/MS amounted to 1,043,331 THB per QALY gained (58,647 I$ per QALY gained). The potential benefits of early detection compared with late detection yielded significant results for PKU, IVA, MSUD, and MCD patients. The budget impact analysis indicated that the implementation cost of the programme was expected at approximately 2,700 million THB (152 million I$) over 10 years. CONCLUSION: At the current ceiling threshold, neonatal screening using MS/MS in the Thai context is not cost-effective. However, the treatment of patients who were detected early for PKU, IVA, MSUD, and MCD, are considered favourable. The budget impact analysis suggests that the implementation of the programme will incur considerable expenses under limited resources. A long-term epidemiological study on the incidence of IEM in Thailand is strongly recommended to ascertain the magnitude of problem.

A simple method for extraction and purification of genomic DNA from dried blood spots on filter paper.

We have developed an efficient and simple method for extracting and purifying genomic DNA from dried blood stored on filter paper. The quality of the genomic DNA extracted is tested by PCR amplification of a 255-bp fragment of the PAX8 gene sequence and the PCR products are determined for further genetic studies by single strand conformation polymorphism (SSCP) analysis. Larger DNA sequences of the 674-bp of the PAX8 gene and the 1,039-bp of the human beta-globin gene, a housekeeping gene, have also been amplified from the extracted DNA, thus indicating the high quality of the genomic DNA extracted by the developed method for subsequent genetic studies of any gene of interest. The method developed can also be used for the purification of genomic DNA from dried blood specimens stored under different conditions. Moreover, the genomic DNA products can be stored for long-term use due to the highly purified procedure. Therefore, the method is efficient and appropriate for the extraction and purification of genomic DNA from dried blood specimens, which has become an increasingly important tool for genetic and epidemiological studies.

Neonatal screening program in Thailand.

The Neonatal Screening Program for congenital hypothyroidism (CHT) and phenylketonuria (PKU) commenced in 1996 with the objective of bringing better quality of life to people throughout the country, especially in the remote areas. This involved the implementation of routine services to the public health infrastructure all over the country. The plan of action has been designed so that by the year 2000 all public health service units throughout the country may provide screening services which can cover 1.2 million babies/ annum. Implementation of the screening program has been performed through public health sectors all over the country. These involved: education of the health personnel and communities, implementation of routine specimens collection and delivery systems to the central laboratories, establishment of central laboratory screening services, routine follow up and case management. Local in-house reagents using ELISA and IRMA techniques have been developed and utilized as screening and confirmation tests for CHT. In addition, Guthrie's test has been used for PKU screening and the automated Fluorometry has been selected for PKU confirmation. All 724 community hospitals have provided newborn screening services as one of the basic requirements for newborns according to public health policy. Of 1,425,025 babies screened, 3,450 (0.24%) were above the first screening cut off for CHT (TSH > 25 mU/l) and 321 (0.02%) for PKU (PKU > 4mg/dl). With a 63.10% follow up rate, the incidences were 1:3,314 for CHT and 1:237,504 for PKU. Newborn screening has been implemented as routine practice for all public health sectors of the country for CHT and PKU. It is expected that by the year 2003, all Thai newborns will be provided with screening services resulting in a better quality of life for the next generation.

Stability of genomic DNA in dried blood spots stored on filter paper.

The stability of DNA in dried blood samples obtained from the neonatal screening program in Thailand was retrospectively studied in order to determine the conditions necessary for the long term storage of samples for DNA banking. Specimens from 1991 to 2001, which had been kept in the ambient conditions at the Department of Medical Science, Ministry of Public Health, Thailand, were randomly sampled and used for the study. Genomic DNA was extracted from the samples and DNA fragments of the PAX8 and beta-globin genes were amplified by PCR to determine DNA stability. The study showed that 255-bp and 674-bp fragments of the PAX8 gene could be amplified from all the samples. The DNA fragment of 1,039 bp of the beta-globin gene could be detected in all of the samples for the years 1993 to 2001, but only in seven and five out of the ten studied samples for each of the years 1991 and 1992, respectively. Our study shows that genomic DNA is stable in dried blood stored on filter paper at ambient tropical conditions for at least 11 years. However, DNA quality for amplification of larger DNA fragments decreased when the specimens were stored for longer than 10 years.

A simple method for extraction and purification of genomic DNA from dried blood spots on filter paper.

We have developed an efficient and simple method for extracting and purifying genomic DNA from dried blood stored on filter paper. The quality of the genomic DNA extracted is tested by PCR amplification of a 255-bp fragment of the PAX8 gene sequence and the PCR products are determined for further genetic studies by single strand conformation polymorphism (SSCP) analysis. Larger DNA sequences of the 674-bp of the PAX8 gene and the 1,039-bp of the human beta-globin gene, a housekeeping gene, have also been amplified from the extracted DNA, thus indicating the high quality of the genomic DNA extracted by the developed method for subsequent genetic studies of any gene of interest. The method developed can also be used for the purification of genomic DNA from dried blood specimens stored under different conditions. Moreover, the genomic DNA products can be stored for long-term use due to the highly purified procedure. Therefore, the method is efficient and appropriate for the extraction and purification of genomic DNA from dried blood specimens, which has become an increasingly important tool for genetic and epidemiological studies.

Neonatal screening program in Thailand.

The Neonatal Screening Program for congenital hypothyroidism (CHT) and phenylketonuria (PKU) commenced in 1996 with the objective of bringing better quality of life to people throughout the country, especially in the remote areas. This involved the implementation of routine services to the public health infrastructure all over the country. The plan of action has been designed so that by the year 2000 all public health service units throughout the country may provide screening services which can cover 1.2 million babies/ annum. Implementation of the screening program has been performed through public health sectors all over the country. These involved: education of the health personnel and communities, implementation of routine specimens collection and delivery systems to the central laboratories, establishment of central laboratory screening services, routine follow up and case management. Local in-house reagents using ELISA and IRMA techniques have been developed and utilized as screening and confirmation tests for CHT. In addition, Guthrie's test has been used for PKU screening and the automated Fluorometry has been selected for PKU confirmation. All 724 community hospitals have provided newborn screening services as one of the basic requirements for newborns according to public health policy. Of 1,425,025 babies screened, 3,450 (0.24%) were above the first screening cut off for CHT (TSH > 25 mU/l) and 321 (0.02%) for PKU (PKU > 4mg/dl). With a 63.10% follow up rate, the incidences were 1:3,314 for CHT and 1:237,504 for PKU. Newborn screening has been implemented as routine practice for all public health sectors of the country for CHT and PKU. It is expected that by the year 2003, all Thai newborns will be provided with screening services resulting in a better quality of life for the next generation.