Associated with the hair forelock, skin pigmentation can also appear in different parts of the body and limbs (suspected to be caused by the mutation in KIT). In parts of the body of some patients, congenital leukoderma is observed.Similar to other types of the syndrome, Type 1 displays heterochromia in some patients, sometimes complete or partial. If it happens to be partial, the differently colored iris is separated from the radial segment of the eye. Deficient iris stroma along with hypoplastic blue arises have also been found in some patients with Type 1. Another one of the symptoms is hearing loss, presenting in about 69% of cases. The types of hearing loss reported in patients differ over a great spectrum. Some of which could be bilateral or unilateral, sensorineural sometimes a combination of different ones in each ear. The most common loss types reported for Type 1 are profound and bilateral. Waardenburg Type 1 is estimated to cause 3% of overall congenital deaf children. Genetics
Type 1 Waardenburg Syndrome is a dominant autosomal disease, with extremely high penetrance of nearly 85%  Type 1, as well as type 3, are linked to a mutation in the PAX3 gene located in chromosome 2q35. This gene is responsible for encoding a transaction factor named Drosophila paired (noted as prd) resulting in essential proteins. These proteins are responsible for multiple functions in early human development such as stem cell pluripotency, as well as inhibition of differentiation when needed and cell-lineage specification, migration, and proliferation in the cells .
A  diagnosis can also be provided through genetic testing and identification of the PAX3 mutation in the patient’s genes. Gene analysis can take on a variety of tests such as single-gene testing (focus on PAX3), a multigene panel (PAX3 along with other genes), and a more comprehensive genomic testing when available.A list of major criteria was created to assess patients for Type 1 Waardenburg Syndrome. The list includes similar features as listed above such as congenital sensorineural hearing loss, white forelock, and hair pigmentation, pigmentation abnormality of the iris, dystopia canthorum, and related family members who exhibit the disease. Management
There is no direct treatment for the patients with Waardenburg Syndrome Type 1, however, there are multiple ways in which the symptoms are managed. There are some options for hearing loss aid depending on the type faced by the patient. In previous cases, cochlea implants were successful to aid the hearing loss. There is also some genetic screening available that can assess whether children can inherit the mutation in the PAX3 gene, but not an overall prediction on the manifestation of the disease in the future generations. Pregnant women who are at risk for children suffering from this disease are recommended Folic acid supplementation to assist with the neural crest development. Further counseling is available with life decisions such as pregnancies and starting families. Since Type 1 is a dominant autosomal disease, any offsprings of those affected are likely to also have the disease.