The Vel weak phenotype is due to a heterozygous deletion in the same exon, resulting one functional copy of the SMIM1 gene. If a patient who is Vel negative is transfused with Vel positive red blood cells, they may form anti-Vel alloantibodies.
Hearing aids need to be fitted by someone trained specifically in hearing problems. An audiologist or licensed hearing aid provider can make sure your hearing aids fit and work for your type and degree of hearing loss. You also need to consider cost.
An open-fit hearing aid is a variation of the behind-the-ear hearing aid with a thin tube. This style keeps the ear canal very open, allowing for low-frequency sounds to enter the ear naturally and for high-frequency sounds to be amplified through the hearing aid.