Solamen syndromeQ85.9

Caux Frédéric 2007

The SOLAMEN Syndrome (SOLAMEN is the acronym for "Segmental Outgrowth (Outgrowth) - Lipomatosis - Arteriovenous Malformation - Epidermal-Naevus Syndrome") is a very rare, autosomal-dominantly hereditary, congenital malformation syndrome with the eponymous main characteristics. The SOLAMEN syndrome is counted among the PTEN hamartoma tumor syndromes . Note: The disease can also be considered a variant of Cowden's syndrome (type 2 segmental Cowden's syndrome).

The frequency is not known, inheritance is autosomal dominant.

The disease is based on mutations in the form of a mosaic in the PTEN gene on chromosome 10 q23.31. The SOLAMEN syndrome only develops if, in addition to the mutation of the PTEN gene known from Cowden's syndrome, a second mutation of the PTEN gene occurs during early embryonic development and is then present in the mosaic (see above). The SOLAMEN syndrome itself is therefore not hereditary.

It is characterized by features of the Cowden syndrome:

• Present at birth: large head, malformations of the urinary tract and vessels.
• Papillomatous skin and mucous membrane proliferations (occurring after the age of 20)
• Lipomas
• Varied, frequently also familial benign and malignant tumours of various types. Organs
• Additionally:
• Local large growth (slight expression).
• Lipohypertrophy
• Malformations of arteries, veins and lymph vessels
• epidermal nevus

Instead of "SOLAMEN", the term "PTEN-Hamartoma-Tumor-Syndrome" has also become established for this clinical picture. See under: Ruvalcaba-Myhre-Smith Syndrome.

The rare syndromes caused by heterozygous defects in PTENs are collectively referred to as PTEN hamartoma tumour syndromes and comprise a group of overlapping heterogeneous syndromes with autosomal dominant PTEN mutations. Due to an incomplete and age-dependent penetrance and varying gene expression, the syndromes show a marked phenotypic heterogeneity. In addition, the mutations known so far are scattered throughout the entire gene, which could also serve as an explanation for the clinical heterogeneity.

1. Caux F et al (2007) Segmental overgrowth, lipomatosis, arteriovenous malformation and epidermal nevus (SOLAMEN) syndromes is related to mosaic PTEN nullizygosity. European journal of human genetics 15: 767-773.