According to Unsal et al., crystalline lenses tended to be thicker in the eyes with clinical PXE than their fellow eyes without PXE,  but in the present study, there was no significant change in LT in cases as compared to controls.
It can be concluded from the present study that raised IOP along with increased AL may predict the future onset of PXE in eyes, which needs closer monitoring to prevent incipient/subclinical glaucoma at an early stage.
Table 1: Ocular parameters in PXE and without PXE Ocular parameters Group n Mean[+ or -]SD Standard error mean IOP Controls 17 12.76[+ or -]3.56 0.86 Cases 14 17.87[+ or -]8.33 2.22 CC (horizontal) Controls 17 45.97[+ or -]2.70 0.65 Cases 14 44.91[+ or -]1.80 0.48 CC (vertical) Controls 17 45.19[+ or -]2.87 0.69 Cases 14 43.80[+ or -]1.69 0.45 LT Controls 17 3.77[+ or -]0.52 0.12 Cases 14 3.88[+ or -]0.67 0.18 ACD Controls 17 3.06[+ or -]0.31 0.07 Cases 14 3.17[+ or -]0.37 0.09 AL Controls 17 22.40[+ or -]0.52 0.12 Cases 14 23.22[+ or -]0.73 0.19 Ocular parameters t P IOP -2.29 0.029 (*) CC (horizontal) 1.25 0.220 CC (vertical) 1.58 0.123 LT -0.47 0.638 ACD -0.82 0.415 AL -3.60 0.001 (*) (*) Statistically significant.
These cases demonstrated that PXE
affects all races and can have myriad manifestations.
The strong expression of ABCC6 in liver and kidney, organs not primarily affected by PXE, lead to the assumption that PXE is a systemic disease (38).
In conclusion, our results show that increased oxidative stress due to genetic variants affecting the activities of antioxidant enzymes leads to an earlier onset of PXE. This finding supports the hypothesis that oxidative stress is involved in the development of disease symptoms.
Acknowledgments: We are grateful to all the PXE patients and their relatives, whose cooperation made this study possible.
ABCC6 mutations in Italian families affected by pseudoxanthoma elasticum (PXE).
Comparison of haplotype block frequencies among PXE patients and controls showed a decreased frequency of the major haplotype A (Table 3) in the PXE group ([P.sub.corrected] = 00345, OR 1.8, 95% CI 1.19-2.71).
We repeated analysis using the PHASE algorithm to compare haplotype patterns in PXE patients and controls.
Allelic frequencies of the 3 SPP1 promoter variants were analyzed in subgroups of the PXE patient groups to evaluate an association with the clinical features shown in Table 1.
PXE is histologically characterized by a progressive calcification and degradation of elastic fibers (1).
We determined the occurrence of the c.3421C>T mutation in PXE patients and their relatives as we have described previously (13, 32).
Fetuin-A was measured in serum samples obtained from 110 patients with PXE, 53 relatives, and 80 healthy blood donors (controls).
We also determined serum calcium and inorganic phosphorus in our cohort of PXE patients and relatives.