DISEASE CARD

Disease group Ectodermal Dysplasia
DISEASE NAME EEC Syndrome
Synonymous Ectrodactyly, Ectodermal Dysplasia, Cleft Lip/palate syndrome
Estimated prevalence -
OMIM 129900, 604292
Inheritance Autosomal Dominant
Gene (s) p63 (603273)

Definition

EEC syndrome is a rare autosomal dominant disorder characterized by ectrodactyly (congenital abnormality involvin g the absence of some fingers or toes), ectodermal dysplasia and cleft l i p or palate. An ass o ciation with p63 gene mutations was first described by Celli et al in 1999. Mutations in this transcription factor ha v e also been identified in other ectoderm a l dysplasia sy n dromes i n cluding A EC (ankyloblepharon-ectodermal dysplasia-clefting; Hay Wells; OMIM 106260) syndrome, limb–mammary syndrome (OMIM 603543), split-h z and split-foot m a lformation syndrome (OMIM 605289), ADULT (acro-dermato-u n gual-lacrimal-tooth) synd r ome (OMIM 103285) and, most recently, Rapp–Hodgkin syndrome (OMIM 129400).

Clinical Description

Infants are born with ectrodactyly, variable ectodermal dysplasia feat u res and cleft lip or palate. Individuals commo n ly have widespread dry, atr o phic and eczematous skin, partial or total alopecia, nail dystrophy and hypodontia. Hair that does develop is abnormal, coarse, w iry and difficult to c o mb. There may also be a r eduction in the numb e r of sweat glands leading to impaired sweating and poor thermoregulation. EEC syndrome is a non-progressive condition. However, there remains great variability of other ectodermal dysplasia f eatures into ad u lthood.

Pathogenesis

Many affe c ted individuals have been found to have mutations within the p63 gene. The mutations are clustered within the DNA binding domain of the gene. The p63 gene is a p53 homolog, and is an important transcription factor in the development of normal s k in and ectodermal structures. However, it’s exact function remains poorly understood. There is increasing evidence to show genotype-phenotype correlation for p63 – associated ectodermal dysplasia syndromes.

Diagnosis

Diagnosis is usually made by assessment of the clinical features either at, or soon after b irth. Genomic DNA should be analysed fo r a p63 gene mutation in o rder to help confirm the diagnosis and assist with genetic counselling. No other diagnostic tests are available at present.

Treatment

The management of the EEC syndrome requires expertise from various medical and surgical specialties. Soon after birth, an affected infant will require surgical repair of his/her cleft lip or palate defects. Topical emollients are required to treat dry, eczematous areas of s k in. Dental treatment is e xtremely important for these i n dividuals as many require successive dentures as a c hild with addition of dental implants and bridges later in ad u lt life. Thermoregulation is vital for those with reduced sweat gla n ds in order t o avoid overheating. This becomes more important during intercurrent illness when high fevers can be potentially life-threatening. Adequate intake of fluids and ensuring air-conditioning is installed at school or the workplace is essential for these individuals