Ocular multi-modal imaging features in an Asian type II Waardenburg syndrome patient: a case report

Waardenburg syndrome (WS) is a rare genetic disorder characterised by congenital hearing loss, pigmentary abnormalities of the hair, skin, and iris, as well as characteristic facial features. Only a few reports have described the ocular findings of WS, and none has performed a thorough ocular imaging examination, especially with regard to choroidal blood flow or morphological differences between hypopigmented iris and choroid. Here, we report a case of type II WS that was investigated using ocular multimodal imaging. A 59-year-old Japanese woman complaining of recent decreased vision was referred to us for cataract surgery and further examination of iris heterochromia. The patient also presented with congenital deafness and piebaldism. Partial depigmentation of the iris was observed at the 12 o’clock position in the right eye and at the 2 o’clock position in the left eye. Fundus examination revealed zonal choroidal hypopigmentation in the upper area in both eyes, corresponding with mild homogeneous hyperautofluorescence demonstrated by fundus autofluorescence and hyporeflectance demonstrated by near infrared reflectance. Swept-source optical coherence tomography (SS-OCT) revealed a thickened choroid with dilated choroidal vessels in the hypopigmented areas, while the overlying retina remained intact. In comparison, the anterior segment OCT (AS-OCT) showed that the hypopigmented iris was slightly thinner than normal iris with no dilated vessels. Both fluorescein angiography and indocyanine green angiography showed slight hyperfluorescence, and laser speckle flowgraphy showed relatively warm colour signal suggesting increased choroidal blood flow in the hypopigmented choroid. A heterozygous variant in the microphthalmia-associated transcription factor ( MITF ) gene (NM_000248.4:c.808C > T, p.Arg270Ter) was detected. Based on congenital hearing loss, white forelock, partial heterochromia irides, absence of dystopia canthorum, and the MITF mutation, the patient was diagnosed with type II WS. The patient underwent cataract surgery in both eyes and pars plana vitrectomy in the left eye due to phacodonesis. The ophthalmic findings of both eyes remained unchanged for one year after surgery. In Asian type II WS with a specific MITF gene mutation, hypopigmentation may lead to different morphological changes between the iris and the choroid, as well as increased choroidal blood flow in the hypopigmented choroidal area.