Distal renal tubular acidosis (RTA) and hereditary elliptocytosis (HE) are apparently distinct, genetic conditions. We report a family with 3 children having both hereditary elliptocytosis and distal renal tubular acidosis. The simultaneous occurrence of these two conditions in three siblings could be due to covariations in the same family, although a possible contiguous gene syndrome for distal RTA and HE cannot be excluded. This report emphasises the importance of excluding a renal tubular defect in any child who presents with elliptocytosis and failure to thrive.
We report a case of renal tubular acidosis (RTA) in a patient with HIV infection and AIDS. A 33-year-old HIV-positive man with Hepatitis C and tuberculous lymphadenitis was admitted due to deep venous thrombosis and generalized muscle weakness. He had never received anti-retroviral medication. The blood gases and serum electrolytes showed hyperchloremic normal anion gap metabolic acidosis with severe hypokalemia and alkaline urine. Diagnosis of distal RTA was made. His renal function and serum globulin level remained within normal range throughout his illness. Clinicians should be alert to renal tubular disorders in HIV/AIDS patients even in the absence of anti-retroviral therapy or hypergammaglobulinemic state.
Southeast Asian ovalocytosis (SAO) is a red blood cell abnormality common in malaria-endemic regions and caused by a 27 nt deletion of the band 3 protein gene. Since band 3 protein, also known as anion exchanger 1, is expressed in renal distal tubules, the incidence of SAO was examined in distal renal tubular acidosis (dRTA) in Malays in Kelantan, Malaysia. Twenty-two patients with dRTA and 50 healthy volunteers were examined for complication of SAO by both morphological and genetic analyses. SAO was identified in 18 of the 22 dRTA patients (81.8%), but only two of the 50 controls (4%). The incidence of SAO was significantly high in those with dRTA (p<0.001), indicating a dysfunctional role for band 3 protein/anion exchanger 1 in the development of dRTA.
Two cases of hypokalaemia with serum potassium levels of 1.4 mmol/L and 1.9 mmol/L causing severe periodic paralysis since childhood are presented. There were associated with muscular aches and markedly raised muscle enzymes suggesting massive rhabdomyolysis. These abnormalities were due to renal tubular acidosis with markedly acidic arterial pH. The hypokalaemia and rhabdomyolysis responded to potassium and bicarbonate replacement. We postulate these patients had sporadic distal type of renal tubular acidosis and that the hypokalaemia and acidosis had caused the rhabdomyolysis.
Familial distal renal tubular acidosis (dRTA) can be caused by mutations in the Cl2/HCO32 exchanger of the renal Type A intercalated cell, kidney AE1/SLC4A1. dRTA-associated AE1 mutations have been reported in families from North America, Europe, Thailand, Malaysia, Papua-New Guinea, Taiwan, and the Philippines, but not India. The dRTA mutation AE1 A858D has been detected only in the context of compound heterozygosity. We report here two unrelated Indian patients with combined hemolytic anemia and dRTA who share homozygous A858D mutations of the AE1/SLC4A1 gene. The mutation creates a novel restriction site that is validated for diagnostic screening.