Genetic counseling for thalassemia in Thailand: problems and solutions.

Thalassemia, a hereditary anemia, has been a major public health problem in Thailand and Southeast Asia for decades, yet the prevalence of thalassemia in Thailand is not decreasing due to lack of awareness of this disease in Thai population, which implied that genetic counseling was a failure. We determined the problems and obstacles in thalassemia counseling in Thailand and proposed the possible solutions in order to deliver genetic counseling and services to the communities more efficiently. A survey in thalassemia services was carried out in 12 hospitals; 9 in Bangkok, 3 in the North, Northeast, and South of Thailand respectively, by using questionnaire designed to assess the healthcare system, characteristics of target population, methods of genetic counseling, knowledge and attitudes of counselors, thalassemia support group, and researches in thalassemia, in a cross-sectional descriptive research design. The main problems in genetic counseling for thalassemia in Thailand are the followings; thalassemia problems not visible to the administrators, unorganized teamwork and services, lack of knowledge and inadequate numbers of counselors, lack of thalassemia support group, and inadequate researches in thalassemia prevention and control. The possible solutions are proposed. This study has pointed out the unseen problems and obstacles, along with the solutions in genetic counseling, given correctly, will help create awareness of thalassemia impact on health and socioeconomics in the Thai population. Thus, genetic counseling, with well-established guidelines, is a critical component for the success of prevention and control of thalassemia in Thailand.

Establishing gas chromatography-mass spectrometry to diagnose organic acidemias in Thailand.

Disorders of organic acid metabolism are a group of disorders which has long been ignored by majority of Thai physicians. Part of this is due to lack of laboratories in Thailand to verify the diagnosis of the disorders. We have recently developed a technique to qualitatively analyze organic acids utilizing Gas Chromatography-Mass Spectrometry (GC-MS). Eight patients in four families were successfully identified as having organic acidemias (OA) by this method. Two families had methylmalonic acidemia, one had propionic acidemia, and the other had 3-methylcrotonyl CoA carboxylase deficiency. To our knowledge, this is the first laboratory in Thailand being able to use GC-MS to diagnose OA. Availability of a laboratory in Thailand and affordability of the test are expected to result in earlier diagnosis and identification of more cases of OA in Southeast Asian countries. Consequently, prompt and proper treatment can be anticipated which should lead to better prognosis for patients with this group of disorder.

Prenatal prediction of spinal muscular atrophy by SMN deletion analysis.

The objective of this study was to provide prenatal prediction of spinal muscular atrophy (SMA) by survival motor neuron (SMN) gene deletion analysis and genetic counseling in families with previous child affected with SMA. The SMN gene is absent or interrupted in approximately 95% of SMA patients independence of clinical severity. We study four families with one previous child affected in each by performing the SMN deletion analysis in the index case. When a homozygous deletion in exon 7 or exon 8 is found, we offer prenatal prediction to the family. All four index cases had homozygous deletions of the SMN gene. Prenatal diagnosis by amniocentesis was performed in all pregnancies. Two pregnancies were positive for the homozygous deletion of the SMN gene, non-directive counseling was given and the two pregnancies were terminated. The other two pregnancies showed no deletion of the SMN gene. The unborn child is yet to be followed up. The prenatal prediction of SMA shows considerable requirements and potential effectiveness in prevention of the SMA in families at risk which cut the cost of care in this incurable disease.

Leber's hereditary optic neuropathy.

A case of Leber's hereditary optic neuropathy (LHON) in a healthy young man who presented with a slow progressive visual loss in one eye and later developed a visual loss in the other eye. There was no pre-existing symptom and no history of visual loss in other family members. Mitochondrial DNA mutation at 11,778 was found in the patient and his uneffected mother and brother. Currently the availability of reliable molecular genetic testing has revolutionized the diagnosis of LHON. LHON is a maternal inherited disorder that causes bilateral visual loss, predominantly in young men. This disorder has been associated with point mutations in the mitochondrial genome which constitute the different clinical phenotypes and prognosis. Genetic counseling in families at risk is recommended.