Genetics
The cytogenetics of EHE gave some of the first clues of an underlying genetic alteration. A balanced, reciprocal translocation t(1;3)(p36.3;q25) in EHE tumor cells was first described by Mendlick et al. in 2001 (Mendlick MR, Nelson M, Pickering D, Johansson SL, Seemayer TA, Neff JR, Vergara G, Rosenthal H, Bridge JA (2001). "Translocation t(1;3)(p36.3;q25) is a nonrandom aberration in epithelioid hemangioendothelioma". Am. J. Surg. Pathol. 25 (5): 684–7. doi:10.1097/00000478-200105000-00019. PMID 11342784. {{cite journal}}:  CS1 maint: multiple names: authors list (link)). This led to the landmark paper by Tanas et al. in 2011(Tanas MR, Sboner A, Oliveira AM, Erickson-Johnson MR, Hespelt J, Hanwright PJ, Flanagan J, Luo Y, Fenwick K, Natrajan R, Mitsopoulos C, Zvelebil M, Hoch BL, Weiss SW, Debiec-Rychter M, Sciot R, West RB, Lazar AJ, Ashworth A, Reis-Filho JS, Lord CJ, Gerstein MB, Rubin MA, Rubin BP (2011). "Identification of a disease-defining gene fusion in epithelioid hemangioendothelioma". Sci Transl Med. 3 (98): 98ra82. doi:10.1126/scitranslmed.3002409. PMID 21885404. {{cite journal}}:  CS1 maint: multiple names: authors list (link)) describing the specific genes involved in the translocation associated with the most common forms of EHE. This alteration results in the fusion of genes coding for two transcription co-activators (transcriptional regulators): TAZ (transcriptional co-activator with PDZ-binding motif) also known as WWTR1 (WW domain-containing transcription regulator protein 1) and CAMTA1 (calmodulin-binding transcription activator 1). The names in parenthesis are not relevant to casual (or even science) readers but are included to help distinguish them from other genes.
Excessive Downward Displacement and Insufficient Downward Displacement
Here on, we will use interchangeably the terms vertical maxillary excess and deficiency with excessive and insufficient downward displacement. In order to understand its manifestations, we need to account for key landmarks such as:· Columella (CM)– The tissue that links the nasal tip to the nasal base, separating the nares. The inferior margin of the nasal septum
· Subnasale (SN) – the junction of the upper lip and the columella
· Stomion Superios (Sts) – the lower most point on the vermillion of the upper lip
· Stomion (Sto) – The point of contact, when lips are competent, in the midline, between the top and bottom lip
· Stomion Inferious (Sti) – the upper most point on the vermillion of the lower lip
· Soft tissue mention (Me) – The most inferior point on the soft tissue outline of the chin
The measurements of the upper lip and lower lip for each patient are ascertained by using the aforementioned landmarks. The length of the upper lip is measured from Sn to Sts. In a typical male and female this measures to 24mm and 21mm respectively (REF). The length of the lower lip is measured from Sti to Me. In a typical male and female this measures to 50mm and 46.5mm respectively.When considering EDD and IDD, the class of the skeletal base is a good adjunct. In other words, EDD and IDD can either appear camouflaged or apparent given the skeletal base and the soft tissue profile accompanying it.