Mode of inheritance & diagnosis

Mode of inheritance

The majority of PHPV cases occur sporadically. A few cases of familial occurrences have been reported in dizygotic twins, in two brothers, and in a mother and son. Autosomal dominant and autosomal recessive genetic forms of PHPV have been described.

PHPV in one eye is not considered a genetic disorder, therefore it should not be passed on by the affected children. However, genetic counseling should be offered to each family with affected child for specific information.

Diagnosis

Diagnosis is based on comprehensive eye examination and confirmed by ultrasonography, computing tomography (CT) or magnetic resonance imaging (MRI). A cone-shaped retrolental density is a characteristic finding of PHPV on imaging studies.

Differential diagnosis

Retinoblastoma (that also typically presents with leukokoria and micropthalmos in the perinatal period) must be primarily concerned in the differential diagnosis of PHPV, as without treatment, most children with retinoblastoma develop life-threatening disease within 2 years.

PHPV is the second most common cause of leukokoria after retinoblastoma. Bilateral cases of PFVS can often be difficult to distinguish from Norrie disease or FEVR.

Other conditions that may easily be mistaken for PHPV include Coats disease, retinopathy of prematurity (ROP), microphthalmia, incontinentia pigmenti, congenital cataract, and ocular toxocariasis.

Diseases rarely confused with PHPV are coloboma of optic nerve, coloboma of posterior pole, uveitis, cataract, myelinated nerve fibers, juvenile xanthogranuloma, falciform retinal folds.