Norrie Disease - Diagnosis

Diagnosis

As of right now, Norrie disease and other NDP related diseases are diagnosed with the combination of clinical findings and molecular genetic testing. Molecular genetic testing identifies the mutations that cause the disease in about 85% of affected males. Clinical diagnoses rely on ocular findings. Norrie disease is diagnosed when grayish-yellow fibrovascular masses are found behind the eye from birth through three months. Doctors also look for progression of the disease from three months through eight-ten years of age. Some of these progressions include cataracts, iris atrophy, shallowing of anterior chamber, and shrinking of the globe. By this point, the vision is light perception impaired or non-existent.

Molecular genetic testing is used for more than an initial diagnosis. It is used to confirm diagnostic testing, for carrier testing females, prenatal diagnosis, and preimplantion genetic diagnosis. There are three types of clinical molecular genetic testing. In approximately 85% of males, mis-sense and splice mutations of the NDP gene and partial or whole gene deletions are detected using sequence analysis. Deletion/duplication analysis can be used to detect the 15% of mutations that are submicroscopic deletions. This is also used when testing for carrier females. The last testing used is linkage analysis, which is used when the first two are unavailable. Linkage analysis is also recommended for those families who have more than one member affected by the disease.