Here I present: “Usher Syndrome (type 2A)”, Victor McKusick, Mendelian Inheritance in Man’, 1966.
INTRODUCTION.
Usher Syndrome is a genetic disorder caused by a mutation in any one of at least 11 genes resulting in a combination of hearing loss and visual impairment. It is the most common cause of deafblindness and is at present incurable.
The Usherin gene encodes the protein Usherin that contains laminin EGF motifs, a pentraxin domain, and many fibronectin type III motifs. The encoded basement membrane-associated protein may be important in development and homeostasis of the inner ear and retina. Mutations within this gene have been associated with Usher syndrome type IIa.
There is evidence Usher syndrome type-IIA (USH2A) is caused by homozygous or compound heterozygous mutation in the gene encoding usherin (USH2A) on cytogenetic location 1q41 and genomic coordinates 1:215,622,891-216,423,448 . The screenshot of the USH2A gene 800,558 bp (base pairs) of DNA sequence length is shown BELOW. Nine (9) other genes besides USH2A in the 1q41 cytogenetic location are listed BENEATH. 
| Coordinate | Symbol | Genomic Name. |
| 1:214,400,001 | RMD1 | Rippling muscle disease 1 |
| 1:214,603,195 | CENPF | Centromere autoantigen F, 400kD |
| 1:215,005,542 | KCNK2 | Potassium channel, subfamily K, member 2 |
| 1:215,567,304 | KCTD3 | Potassium channel tetramerization domain protein 3 |
| 1:215,622,891 | USH2A | Usherin |
| 1:216,503,246 | ESRRG | Estrogen-related receptor, gamma |
| 1:217,426,992 | GPATCH2 | G-patch domain-containing protein 2 |
| 1:217,631,344 | SPATA17 | Spermatogenesis-associated protein 17 |
| 1:218,285,293 | RRP15 | Ribosomal RNA-processing 15 homolog |
| 1:218,345,336 | TGFB2 | Transforming growth factor, beta-2 |
