Interestingly, PHA1 is the only salt-wasting tubulopathy associated with hyponatraemia, presumably because the hypovolaemia triggers release of anti-diuretic hormone and with urinary concentration intact, the low solute intake of milk-fed babies in conjunction with a concentrated urine leads to progressive hyponatraemia, aggravated by the urinary sodium losses [20]. Here, AVP is linked to Hyponatremia.