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Table 1 Classification systems applied to amelogenesis imperfecta

From: Amelogenesis imperfecta

Weinmann et al., 1945 [4]

Two types based solely on phenotype: hypoplastic and hypocalcified

Darling, 1956 [5]

Five phenotypes based on clinical, microradiographic and histopathological findings.

 

Hypoplastic

 

Group 1 – generalised pitting

 

Group2 – vertical grooves (now known to be X-linked AI)

 

Group 3 – Generalised hypoplasia

 

Hypocalcified

 

Type 4A – chalky, yellow, brown enamel

 

Type 4B – marked enamel discolouration and softness with post-eruptive loss of enamel

 

Type 5 – generalised or localised discolouration and chipping of enamel

Witkop, 1957 [6]

Classification based primarily on phenotype. 5 types:

 

1. Hypoplastic

 

2. Hypocalcification

 

3. Hypomaturation

 

4. Pigmented hypomaturation

 

5. Local hypoplasia

 

Added mode of inheritance as further means of delineating cases.

Schulze, 1970 [7]

Classification based on phenotype and mode of inheritance.

Witkop and Rao, 1971 [8]

Classification based on phenotype and mode of inheritance. Three broad categories: hypoplastic, hypocalcificied, hypomaturation.

 

a. Hypoplastic

 

Autosomal dominant hypoplastic-hypomaturation with taurodontism (subdivded into a and b according to author)

 

Autosomal dominant smooth hypoplastic with eruption defect and resorption of teeth

 

Autosomal dominant rough hypoplastic

 

Autosomal dominant pitted hypoplastic

 

Autosomal dominant local hypoplastic

 

X-linked dominant rough hypoplastic

 

b. Hypocalcified

 

Autosomal dominant hypocalcified

 

c. Hypomaturation

 

X-linked recessive hypomaturation

 

Autosomal recessive pigmented hypomaturation

 

Autosomal dominant snow-capped teeth

 

White hypomature spots?

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

 

Type I. Autosomal dominant thin and smooth hypoplasia with eruption defect and resorption of teeth

 

Type II. Autosomal dominant thin and rough hypoplasia

 

Type III. Autosomal dominant randomly pitted hypoplasia

 

Type IV. Autosomal dominant localised hypoplasia

 

Type V. X-linked dominant rough hypoplasia

 

b. Hypocalcification

 

Autosomal dominant hypocalcification

 

c. Hypomaturation

 

Type I. X-linked recessive hypomaturation

 

Type II. Autosomal recessive pigmented hypomaturation

 

Type III. Snow-capped teeth

 

d. Hypomaturation-hypoplasia with taurodontism

 

Type I. Autosomal dominant smooth hypomaturation with occasional hypoplastic pits and taurodontism

 

Type II. Autosomal dominant smooth hypomaturation with thin hypoplasia and taurodontism

Witkop and Sauk, 1976 [2]

Classification based on phenotype and mode of inheritance, similar to classification of Witkop and Rao (1971)

Sundell and Koch, 1985 [10]

Classification based solely on phenotype

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

 

Type IA. Hypoplastic, pitted autosomal dominant

 

Type IB. Hypoplastic, local autosomal dominant

 

Type IC. Hypoplastic, local autosomal recessive

 

Type ID. Hypoplastic, smooth autosomal dominant

 

Type IE. Hypoplastic, smooth X-linked dominant

 

Type IF. Hypoplastic, rough autosomal dominant

 

Type IG. Enamel agenesis, autosomal recessive

 

Type II. Hypomaturation

 

Type IIA. Hypomaturation, pigmented autosomal recessive

 

Type IIB. Hypomaturation, X-linked recessive

 

Type IIC. Hypomaturation, snow-capped teeth, X-linked

 

Type IID. Hypomaturation, snow-capped teeth, autosomal dominant?

 

Type IIIA. Autosomal dominant

 

Type IIIB. Autosomal recessive

 

Type IV. Hypomaturation-hypoplastic with taurodontism

 

Type IVA. Hypomaturation-hypoplastic with taurodontism, autosomal dominant

 

Type IVB. Hypoplastic-hypomaturation with taurodontism, autosomal dominant

Aldred and Crawford, 1995 [12]

Classification based on:

 

Molecular defect (when known)

 

Biochemical result (when known)

 

Mode of inheritance

 

Phenotype

Hart et al., 2002 [13]

Proposed a molecular defect sub classification of the AMELX conditions

 

1.1 Genomic DNA sequence

 

1.2 cDNA sequence

 

1.3 Amino acid sequence

 

1.4 Nucleotide and amino-acid sequences

 

1.5 AMELX mutations described to date

Aldred et al., 2003 [1]

Classification based on:

 

Mode of inheritance

 

Phenotype – Clinical and Radiographic

 

Molecular defect (when known)

 

Biochemical result (when known)