[Clinical characteristics and genetic analysis of a Chinese pedigree affected with thiamine pyrophosphokinase deficiency].

OBJECTIVE

To investigate the clinical characteristics and genetic variant in a Chinese pedigree affected with thiamine pyrophosphokinase deficiency (TPKD).

METHODS

Clinical data of the pedigree were analyzed retrospectively and summarized from the perspectives of clinical manifestation, magnetic resonance imaging (MRI), and genotype. Relevant literature was also reviewed.

RESULTS

The proband, a female, has developed paroxysmal ataxia with dystonia at the age of 2-year-and-8-month. The ataxia has recurred for 7-8 times. The child had died at 11 years old due to recurrence and aggravation of the disease. MRI showed diffuse symmetrical lesions of brain parenchyma and spinal cord. Her brother had similar symptoms and died at 6. The parents were consanguineous but healthy. Genetic testing revealed that the girl has carried homozygous c.161C>T variants of the TPK1 gene, suggesting the diagnosis of TPKD. So far 15 cases of TPKD have been reported, among which 9 were from consanguineous marriages. The disease usually occurs before the age of 3, and most patients had featured paroxysmal encephalopathy and recurrent infections. Symmetrical celebral cortex, basal ganglia and cerebellum lesions were common. Missense mutations of the TPK1 gene were common. Vitamin B1 was effective in some cases.

CONCLUSION

For infants featuring encephalopathy, ataxia, dystonia and other phenotypes, early genetic testing should be recommended in order to provide guidance for clinical treatment and genetic counseling.