Table 1

Classification systems applied to 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.


Group 1 – generalised pitting

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

Group 3 – Generalised hypoplasia


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


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)

Crawford et al. Orphanet Journal of Rare Diseases 2007 2:17   doi:10.1186/1750-1172-2-17

Open Data