Peptide Bound Hypohydroxyprolinuria in Handigodu Disease: A Familial Syndrome of Spondylo Epi(meta)physeal Dysplasia

Abstract

Handigodu Disease (HD) is disorder of the osteoarticular system prevalent in few villages of two districts of the state Karnataka in southern India. 24 hrs urinary excretions of proline (Pro) and 4-hydroxyproline (Hyp) were analyzed by HPLC. Decreased peptide bound Hyp excretions (μmole/24 hrs) were found in patient group when compared with controls (Nonaffected; 113.02 ± 67.96, Type-I; 36.22 ± 20.76, Type-II; 45.74 ± 14.95, Type-III; 40.46 ± 22.68) and without significant difference in Pro excretions. Significant increased peptide bound Pro to Hyp ratio were found in patient group compared to control (Nonaffectedn= 63: 2.02 ± 1.65, Type-In= 18: 3.144 ± 1.42, Type-IIn= 28: 4.21 ± 1.95, Type-IIIn= 8: 8.60 ± 6.55). 24 hrs urinary excretions of deoxypyridinoline (DPD) crosslinks were found without significant difference among affected and control, hence HD ruled out from general bone reduction. These results suggest hypohydroxyprolinuria may be because of reduced bone turnover or defective hydroxylation of prolyl residues during post translational modification of collagen biosynthesis.