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Focal facial dermal dysplasia type IV
Disease definition
Focal facial dermal dysplasia type IV (FFDD4) is a rare focal facial dysplasia (FFDD; see this term), characterized by congenital isolated preauricular and/or cheek blister scar-like lesions.
ORPHA:398189
Classification level: Subtype of disorderSummary
Epidemiology
To date, FFDD4 is reported in over 20 patients.
Clinical description
FFDD4 is characterized by isolated congenital bilateral hypoplastic atrophic skin lesions distributed in a distinctive, curvilinear manner between the maxillary and manibular prominences in the preauricular region and/or cheek. Affected FFDD4 patients typically do not present with extra-cutaneous manifestations, although in a small number of cases, a hair collar sign (circumscription of the cutaneous lesion with terminal hairs), polyps on the buccal mucosa with a similar distribution pattern, and developmental delay have been reported.
Etiology
FFDD4 is caused in a subset of affected cases (four out of five unrelated families) by a 7 base pair duplication, c.844_851dupCCATGCA (p. p.Glu284fsX128) or a missense mutation, c.1433G>A (p.Arg478His) in the CYP26C1 gene, which is involved in retinoic acid metabolism and important in the formation of the mandibular and maxillary prominences. The short duplication occurs in 0.3% of the healthy control population, suggesting that heterozygosity for the alteration does not result in phenotypic manifestations.
Diagnostic methods
FFDD4 is diagnosed in patients with isolated preauricular scar-like lesions, typically in the absence of other manifestations. These patients were homozygous for the seven base pair duplication or were heteroallelic for the seven base pair duplication and the missense mutation in the CYP26C1 gene. Histologic findings include epidermal atrophy with the presence of loose connective tissue replacing the dermis, diminished fragmented elastic tissue, and a lack of subcutaneous tissues and adnexal structures.
Differential diagnosis
Differential diagnosis may include membranous aplasia cutis congenita (see this term), but in FFDD4 cutaneous lesions are isolated and do not occur in combination with other extra-cutaneous manifestations.
Genetic counseling
Appropriate counseling should be provided for this autosomal recessive trait. The fact that not all the patients with FFDD4 had CYP26C1 mutations indicates the occurrence of genetic heterogeneity for this developmental disorder.
Management and treatment
There is limited experience with plastic surgery for the facial scar-like lesions
Prognosis
Affected individuals have normal life span.
A summary on this disease is available in Español (2014) Nederlands (2014)
Additional information