Araya Jintaviwat. Analysis of genes encoding subunits of hydrogen-potassium ATPase (H+/K+-ATPase) in Northeastern thai patients with distal renal tubular acidosis and hypokalemia . Master's Degree(Immunology). Mahidol University. : Mahidol University, 2006.
Analysis of genes encoding subunits of hydrogen-potassium ATPase (H+/K+-ATPase) in Northeastern thai patients with distal renal tubular acidosis and hypokalemia
Abstract:
Kidney and kidney related disorders in association with hypokalemia especially distal
renal tubular acidosis (dRTA) and acidification defect (AD) are frequently observed in
northeastern (NE) Thai population. Although attempts have been made to identify molecular
defects of several transporters and proteins that may be involved in abnormal acid-base
balance, the pathogenesis of these disorders in the NE Thai population have not been
elucidated. H+/K+-ATPase is a transporter that plays a critical role in maintenance of
potassium homeostasis in association with acid-base balance. It is thus proposed that defect
of H+/K+-ATPase is involved in pathogenesis of dRTA and AD associated with hypokalemia
in the NE Thai population. ATP4A, ATP12A, and ATP4B genes encoding gastric α-,
nongastric α-, and β-subunits of H+/K+-ATPase were analyzed in the NE Thai patients with
dRTA or AD with hypokalemia by polymerase chain reaction (PCR) and denaturing high
performance liquid chromatography (DHPLC) followed by DNA sequencing to screen
nucleotide variations in these genes. The possible mutations and single nucleotide
polymorphisms (SNPs) identified were then evaluated for significance in causing the disease
by examination of their alteration types and locations and their association with the disease in
the patient group and within the families. In the analysis of 10 patients with dRTA and 5
patients with AD with hypokalemia, and 7 normal controls by PCR and DHPLC, 19 of 48
amplified fragments showed multiple elution DHPLC profiles, which were further analyzed
by DNA sequencing. Fourteen known and five novel SNPs were identified. Four SNPs
represented by four specific DHPLC profiles were observed only in the patient group but not
in the control group. However, these four SNPs did not co-segregate with the disease when
they were analyzed in the affected families, indicating that they were unlikely to be disease
causing mutations. There was no disease causing mutation identified in ATP4A, ATP12A, and
ATP4B encoding subunits of H+/K+-ATPase in the group of patients with dRTA or AD
studied. However, the role of these genes in causing dRTA and AD in the NE Thai population
could not absolutely be ruled out. Further study with a larger number of patients and controls,
and with other approaches such as genome-wide association, are required to prove the role of
these or other genes in pathogenesis of the disease