SSPS is inherited in an autosomal recessive fashion. The disorder is caused by mutations in the WNT10A gene on chromosome 2q35, which codes for a signaling molecule involved in the regulation of cell to cell interactions, a key player in embryogenesis. Sporadic cases have also been reported.
The diagnosis of SSPS is often delayed, as numerous features of the syndrome present after childhood.
Eyelid apocrine hidrocystomas are the most consistent finding of SSPS. They are reported to develop predominantly in adulthood with a mean age of 60 years at diagnosis. There is wide variation in syndrome phenotype, and these hidrocystomas may rarely be the sole manifestation.
The majority of individuals with SSPS have abnormal dentition. Hypodontia is the most frequent finding, but oligodontia, anodontia, conical teeth, and/or hypoplasia of the alveolar processes may be seen. Deciduous teeth may be normal, and onset of hypodontia may therefore occur when deciduous teeth are lost.
The onset of PPK, hypotrichosis, and onychodystrophy is variable; cases with onset in childhood through early adulthood have been reported.
While SSPS has been associated with eccrine syringofibroadenoma, basal cell carcinoma, porocarcinoma, squamous cell carcinoma, and a single case of malignant eccrine syringofibroadenoma, the neoplastic risk of SSPS is debatable. Patients with SSPS have normal life expectancy, and SSPS is generally not considered a cancer-prone syndrome.
Q82.8 – Other specified congenital malformations of skin
700062000 – Schöpf-Schulz-Passarge syndrome
Differential Diagnosis & Pitfalls
- Odonto-onycho-dermal dysplasia (OODD) – similar manifestations as SSPS, but absence of eyelid apocrine hidrocystomas; facial erythema and atrophic glossitis may be seen
- Hypohidrotic ectodermal dysplasia
- Hidrotic ectodermal dysplasia
- Clouston syndrome – autosomal dominant; characterized by PPK, onychodystrophy, and hypotrichosis
- Papillon-Lefevre syndrome (PLS) – characterized by PPK and severe periodontal disease
- Focal dermal hypoplasia (FDH; Goltz syndrome) – X-linked dominant; characterized by skin abnormalities from birth as well as skeletal abnormalities of the hands and feet