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Classification systems applied to amelogenesis imperfecta |
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| Weinmann et al., 1945 [4] |
Two types based solely on phenotype: hypoplastic and hypocalcified |
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| Darling, 1956 [5] |
Five phenotypes based on clinical, microradiographic and histopathological findings. |
| Hypoplastic |
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| Group 1 – generalised pitting |
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| Group2 – vertical grooves (now known to be X-linked AI) |
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| Group 3 – Generalised hypoplasia |
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| Hypocalcified |
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| Type 4A – chalky, yellow, brown enamel |
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| Type 4B – marked enamel discolouration and softness with post-eruptive loss of enamel |
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| Type 5 – generalised or localised discolouration and chipping of enamel |
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| Witkop, 1957 [6] |
Classification based primarily on phenotype. 5 types: |
| 1. Hypoplastic |
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| 2. Hypocalcification |
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| 3. Hypomaturation |
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| 4. Pigmented hypomaturation |
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| 5. Local hypoplasia |
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| Added mode of inheritance as further means of delineating cases. |
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| Schulze, 1970 [7] |
Classification based on phenotype and mode of inheritance. |
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| Witkop and Rao, 1971 [8] |
Classification based on phenotype and mode of inheritance. Three broad categories: hypoplastic, hypocalcificied, hypomaturation. |
| a. Hypoplastic |
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| Autosomal dominant hypoplastic-hypomaturation with taurodontism (subdivded into a and b according to author) |
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| Autosomal dominant smooth hypoplastic with eruption defect and resorption of teeth |
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| Autosomal dominant rough hypoplastic |
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| Autosomal dominant pitted hypoplastic |
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| Autosomal dominant local hypoplastic |
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| X-linked dominant rough hypoplastic |
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| b. Hypocalcified |
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| Autosomal dominant hypocalcified |
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| c. Hypomaturation |
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| X-linked recessive hypomaturation |
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| Autosomal recessive pigmented hypomaturation |
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| Autosomal dominant snow-capped teeth |
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| White hypomature spots? |
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| Winter and Brook, 1975 [9] |
Classification based primarily on phenotype. Four main categories: hypoplasia, hypocalcification, hypomaturation, hypomaturation-hypoplasia with taurodontism, with mode of inheritance as a secondary means of sub-classification. |
| a. Hypoplasia |
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| Type I. Autosomal dominant thin and smooth hypoplasia with eruption defect and resorption of teeth |
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| Type II. Autosomal dominant thin and rough hypoplasia |
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| Type III. Autosomal dominant randomly pitted hypoplasia |
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| Type IV. Autosomal dominant localised hypoplasia |
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| Type V. X-linked dominant rough hypoplasia |
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| b. Hypocalcification |
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| Autosomal dominant hypocalcification |
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| c. Hypomaturation |
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| Type I. X-linked recessive hypomaturation |
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| Type II. Autosomal recessive pigmented hypomaturation |
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| Type III. Snow-capped teeth |
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| d. Hypomaturation-hypoplasia with taurodontism |
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| Type I. Autosomal dominant smooth hypomaturation with occasional hypoplastic pits and taurodontism |
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| Type II. Autosomal dominant smooth hypomaturation with thin hypoplasia and taurodontism |
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| Witkop and Sauk, 1976 [2] |
Classification based on phenotype and mode of inheritance, similar to classification of Witkop and Rao (1971) |
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| Sundell and Koch, 1985 [10] |
Classification based solely on phenotype |
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| Witkop, 1988 [11] |
Four major categories based primarily on phenotype (hypoplastic, hypomaturation, hypocalcified, hypomaturation-hypoplastic with taurodontism) subdivided into 15 subtypes by phenotype and and secondarily by mode of inheritance. |
| Type I. Hypoplastic |
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| Type IA. Hypoplastic, pitted autosomal dominant |
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| Type IB. Hypoplastic, local autosomal dominant |
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| Type IC. Hypoplastic, local autosomal recessive |
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| Type ID. Hypoplastic, smooth autosomal dominant |
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| Type IE. Hypoplastic, smooth X-linked dominant |
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| Type IF. Hypoplastic, rough autosomal dominant |
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| Type IG. Enamel agenesis, autosomal recessive |
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| Type II. Hypomaturation |
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| Type IIA. Hypomaturation, pigmented autosomal recessive |
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| Type IIB. Hypomaturation, X-linked recessive |
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| Type IIC. Hypomaturation, snow-capped teeth, X-linked |
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| Type IID. Hypomaturation, snow-capped teeth, autosomal dominant? |
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| Type IIIA. Autosomal dominant |
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| Type IIIB. Autosomal recessive |
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| Type IV. Hypomaturation-hypoplastic with taurodontism |
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| Type IVA. Hypomaturation-hypoplastic with taurodontism, autosomal dominant |
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| Type IVB. Hypoplastic-hypomaturation with taurodontism, autosomal dominant |
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| Aldred and Crawford, 1995 [12] |
Classification based on: |
| Molecular defect (when known) |
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| Biochemical result (when known) |
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| Mode of inheritance |
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| Phenotype |
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| Hart et al., 2002 [13] |
Proposed a molecular defect sub classification of the AMELX conditions |
| 1.1 Genomic DNA sequence |
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| 1.2 cDNA sequence |
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| 1.3 Amino acid sequence |
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| 1.4 Nucleotide and amino-acid sequences |
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| 1.5 AMELX mutations described to date |
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| Aldred et al., 2003 [1] |
Classification based on: |
| Mode of inheritance |
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| Phenotype – Clinical and Radiographic |
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| Molecular defect (when known) |
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| Biochemical result (when known) |
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Crawford et al. Orphanet Journal of Rare Diseases 2007 2:17 doi:10.1186/1750-1172-2-17 |
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