Blood: Draw blood in a lavender top EDTA tube, Sample Stability: 5-7 days, Preferred volume: 4 ml, Minimum volume: 2 ml, DO NOT FREEZE. Extracted DNA: From leukocytes, muscle, or fibroblasts: Preferred quantity: 1 microgram, Minimum quantity: 800 nanograms. Genomic DNA should be eluted in sterile Dnase/Rnase free water or TE. The A260:A280 ratio should be 1.8-2.0. Cultured Fibroblasts: Two T-25 flasks of fibroblasts, preferably ~90% confluent. TAT will be extended by 7-14 days if cells are not confluent upon arrival. Muscle: 50-75 milligrams muscle snap frozen in liquid nitrogen and maintained at -80°Celsius or below. Buccal Cells: One buccal swab should be used for collection. Do not discard solution in collection tube. Follow collection instructions supplied. Stability at ambient temperature is 60 days.
Blood: Specimens should be shipped overnight in a secure container at room temperature. Extracted DNA: Should be shipped overnight at room temperature. If previously frozen, DNA can be shipped in an insulated container with wet or dry ice. Cultured Fibroblasts: T-25 flasks containing fibroblasts should be shipped in an insulated container at room temperature. Flasks should be completely filled with media and cells should be ~90% confluent. Fibroblast samples must be certified free from Mycoplasma. MNG is able to perform this service for a small charge (TC05). For NGS panels, TAT will be extended by 7-14 days if cells are not confluent upon arrival. Muscle: Samples should be shipped frozen in an insulated container with 5-7 lbs. dry ice, overnight. Buccal cells: Should be shipped overnight in a secure container at room temperature.
Blood - ship ASAP, but stable up to 5 days post-collection at room temperature. DO NOT FREEZE; Swab - 60 day post-collection room temperature stability; DNA - ship at room temperature after extraction; Fibroblasts - ship flask in insulated container at room temp or refigerated; Muscle - ship in insulated container with 5-7 lbs of dry ice
Extracted DNA A260:A280 ratio of outside of 1.8-2.0 range; Frozen blood EDTA tube; Thawed and/or fatty muscle sample; Insufficient buccal cell collection
Usher syndrome is an autosomal recessive condition characterized by partial or total hearing loss, and vision loss that worsens over time. The hearing loss is classified as sensorineural, meaning that it is caused by abnormalities of the inner ear. The loss of vision is caused by retinitis pigmentosa (RP), a progressive, bilateral, symmetric degeneration of rod and cone functions of the retina. Night vision loss begins first, followed by blind spots that develop in the peripheral vision. Over time, these blind spots enlarge and lead to ‘tunnel vision.’ In some cases, vision is further impaired by cataracts. However, many people with RP retain some central vision throughout their lives. The most common forms of Usher syndrome are types I, II, and III.
Most individuals with Usher syndrome type I are born with severe to profound hearing loss. Unless fitted with a cochlear implant, affected children do not typically develop speech. Progressive vision loss caused by RP becomes apparent in childhood.
Usher syndrome type II is characterized by hearing loss from birth and progressive vision loss caused by RP that begins in adolescence or adulthood. The hearing loss associated with this form of Usher syndrome ranges from mild to severe and mainly affects the ability to hear high-frequency sounds. The degree of hearing loss varies within and among families with this condition, and it may become more severe over time.
Those with Usher syndrome type III experience hearing loss and vision loss beginning somewhat later in life. Unlike the other forms of Usher syndrome, type III is usually associated with normal hearing at birth. Hearing loss typically begins during late childhood or adolescence, after the development of speech, and becomes more severe over time. By middle age, most affected individuals have profound hearing loss. Vision loss caused by RP also develops in late childhood or adolescence.
Recommended MNG Kits
SINGLE Blood Genetic Testing, Buccal Swab Genetic Testing