Non-syndromic isolated congenital deafness was found in 2 other family members, although they were otherwise unaffected.The third case report was made by Valero et al in 2008, they described a 60-year old man and his 81-year-old mother from France. The both of them had noninsulin-dependent diabetes mellitus and childhood-onset hearing loss. Out of the 2 patients, the mother was the most affected, her phenotype consisted of additional features her son didnt suffer from including severe vision impairment, bilateral optic nerve atrophy. Even though both of them had hearing impairments, the son was the only one of the pair who wore a hearing aid, the mother didnt do so, and as a result she had very obvious difficulties comprehending speech.The fourth case report was made by Hogewind et al, their patients were 3 affected members of a 2-generation Dutch family (2 brothers and their mother). The three of them suffered from hearing loss ranging from moderate to severe and optic neuropathy but they didnt have any other symptoms, including the ones usually associated with both Wolfram syndrome and Wolfram-like syndrome (such as diabetes mellitus/insipidus or depression), but they did have red-green color deficiency. The elder sibling and the mother were found to have severe hearing loss which heavily diminished their ability at recognizing speech, while the younger brother was relatively okay at doing so. All three individuals were found to have ocular scotoma (also known as blind spot) and neuroretinal rim loss.
Genetics
This condition is caused by mutations in the WFS1 gene, these mutations are inherited in an autosomal dominant manner, meaning that for a person to exhibit the symptoms of Wolfram-like syndrome, they must have at least one copy of the mutation that is responsible for the phenotype of the disorder, this mutation is usually inherited, but there are cases where the mutation is de novo, meaning that it wasnt inherited from either parent, but rather the result of a spontaneous error in cell division.This gene encodes a protein called wolframin, the mutations typically found in people with this condition cause the production of a protein that is either absent or has little to no function at all.Mutations in this gene are also associated with other disorders affecting vision or hearing, (aside from Wolfram syndrome) such as non-syndromic autosomal dominant deafness type 6., isolated autosomal dominant congenital cataract, etc. In rare cases, a mutation in the CDK13 gene instead of the WFS1 gene is responsible for the disorder, this genetic mutation has only been described in 3 affected children belonging to a consanguineous Pakistani family who, in addition to the typical symptoms of the disorder, also had anomalies affecting the gastrointestinal tract, congenital heart defects, and clinodactyly.