Type 3 renal tubular acidosis associated with growth hormone deficiency

Background:We identified two boys with type 3 renal tubular acidosis (RTA) and growth hormone deficiency and we sought to differentiate them from children with classic type 1 distal RTA.Methods:We reviewed all children Results:All children with type 1 RTA reached the 5th percentile or higher on CDC growth charts within 2 years of alkali therapy. Their mean height standard deviation score (SDS) improved from −1.4 to −0.6 SDS and their mean mid-parental height (MPH) SDS improved from −0.6 to 0 SDS after 2 years. In contrast, the boys with growth hormone deficiency had a height SDS of −1.4 and −2.4 SDS after 2 years of alkali and the MPH SDS were both −2.6 SDS after 2 years of alkali therapy. Growth hormone therapy accelerated their growth to normal levels and led to long-term correction of RTA.Conclusions:A child with type 1 RTA whose height response after 2 years of alkali therapy is inadequate should undergo provocative growth hormone testing.