Screening for Chromosomal Microarrangements by CGH-array in Developmental Anomalies of the Skin Suggestive of Mosaicism.

Screening for Chromosomal Microarrangements by CGH-array in Developmental Anomalies of the Skin Suggestive of Mosaicism. National Multicentre Descriptive Study.

The principal result expected is the discovery of inframicroscopic chromosomal rearrangements in regions of the genome not yet known to be involved, or mutations in known candidate genes;

The identification of such a mosaic rearrangement in an affected infant would lead to improved genetic counselling. Indeed, as this mosaicism is a consequence of a genetic event occurring at an early stage of embryogenesis, it would be possible to confirm the sporadic nature of the observed disorder and therefore to predict a very low or even negligible risk of recurrence for the couple concerned. For the affected infant, the risk for his/her own offspring will be assessed according to the nature of the genetic anomaly discovered. For medical practice, investigators hope that this study will lead to a clearer definition of the screening modalities for mosaicism in the disorders concerned. In particular, they hope to determine whether or not it is possible to dispense with a skin biopsy, which is more invasive than a blood sample.

Inclusion Criteria:

• Persons who have provided written informed consent
• Lower age limit: infant born at more than 37 WA
• Sporadic disorder
• Patients presenting at least two skin criteria, or one skin criterion and one non-skin criterion
• Skin criteria: 1- extensive epidermal or sebaceous naevus, 2- Extensive "segmental" haemangioma, 3- Flat angioma or extensive complex vascular malformation, 4-Pigmentary disorders with patterns suggesting mosaicism (Blaschko lines)
• Non-skin criteria: Cerebral, ocular, cardiac or genito-urinary malformation, asymmetric body, segmental hypertrophy of a limb, spinal dysraphism (only when associated with haemangioma)

Exclusion Criteria:

• Persons not covered by the national health insurance scheme
• Mendelian disorders: CM-AVM syndrome, glomangiomatosis, Cowden or Bannayan syndrome, type 1 neurofibromatosis, incontinentia pigmenti, CHILD syndrome, Happle-type chondrodysplasia punctata
• Mendelian mosaic disorders: epidermal or epidermolytic, comedo or dyskeratotic nevus.
• Family history of one of these disorders
• Suspicion or an autosomal dominant disease
• Patient and/or parent under guardianship or ward of court