Here I present: “Shields Dentin Dysplasia”, Victor McKusick, Mendelian Inheritance in Man’, 1966. 盾牌牙齒發育不良。(DTDP2).
INTRODUCTION.
Dentin dysplasia (DD) is a genetic developmental disorder affecting dentine production of the teeth, commonly exhibiting an autosomal dominant inheritance that causes malformation of the root. It affects both primary and permanent dentitions. It is characterized by the presence of normal enamel but atypical dentin with abnormal pulpal morphology.
The classification of DD is into two types which are Type-1 (DD-1) is the radicular type, and type-2 (DD-2) is the coronal type. DD-1 has been further divided into 4 different subtypes (DD-1a,1b,1c,1d) based on the radiographic features.
There is evidence Shields Dentin Dysplasia type-2 is caused by heterozygous mutation in the (DTDP2) gene which encodes dentin sialophoshoprotein on cytogenetic location 4q22.1 and genomic coordinates 4:87,608,529-87,616,873. The screenshot of the DTDP2 gene 8,345 bp (base pairs) of DNA sequence length is shown BELOW. Nine (9) other genes DTDP2 in the 4q22.1 cytogenetic location are listed BENEATH. It should be noted that the dentin sialophosphoprotein is associated with four (4) clinically related disorders at genomic coordinate 4:87,698,529 on cytogenetic location 4q22.1 (listed BELOW).
| Coordinate | Symbol | Genomic Name |
| 4:87,303,794 | HSD17B13 | 17-beta-hydroxysteroid dehydrogenase XIII |
| 4:87,336,515 | HSD17B11 | 17-beta-hydroxysteroid dehydrogenase XI |
| 4:87,422,573 | NUDT9 | Nudix hydrolase 9 |
| 4:87,473,335 | SPARCL1 | SPARC-like protein 1 |
| 4:87,608,529 | DTDP2 | Dentin sialophosphoprotein |
| 4:87,650,280 | DMP1 | Dentin matrix acidic phosphoprotein |
| 4:87,799,554 | IBSP | Integrin-binding sialoprotein |
| 4:87,821,398 | MEPE | Matrix, extracellular, phosphoglycoprotein |
| 4:87,975,714 | SPP1 | Secreted phosphoprotein-1 |
| 4:88,007,635 | PKD2 | Polycystin-2 |
| Dentinogenesis Disorders @ 4:87,608,529 (4q22.1) |
| Dentin sialophosphoprotein |
| Deafness, autosomal dominant 39, with dentinogenesis |
| Dentin dysplasia, type II |
| Dentinogenesis imperfecta, Shields type II |
| Dentinogenesis imperfecta, Shields type III |
