What are the characteristics, signs, and symptoms of 1p36 deletion syndrome?
Unfortunately, for the affected individuals and family, missing DNA in this section is very influential on a person's overall development and is often unnoticed until the newborn or infant is noted to miss physical or developmental landmarks. These landmarks that are missed or severely delayed comprise the symptoms and signs of 1p36 deletion syndrome. Not all symptoms will be present in each individual because there is variation from person to person and, in general, most researchers think that the more DNA missing from 1p36, the more intense or apparent these symptoms will appear.
Many individuals will have a small head size that is short and wide; many have noticeable facial features of deep-set eyes with straight-appearing eyebrows, a sunken–appearing face with a broad flat nose and an elongated area from nose to mouth, a pointed chin, and low-set ears that are rotated backwards and are abnormally shaped. Some individuals are preliminarily diagnosed from their appearance described above. Others may have less noticeable physical symptoms and require FISH or CGH tests for diagnosis.
To confirm or establish the diagnosis it is appropriate to test any individual suspected of having 1p36 deletion syndrome as follows:
- Conventional cytogenetic studies to detect large deletions (i.e., > 5 Mb) and more complex cytogenetic rearrangements (unbalanced chromosome translocations)
- FISH with at least two subtelomeric region-specific probes (Vysis 1p subtel probe, Vysis p58 probe; D1Z2 Oncor probe or CEB108/T7) to detect unbalanced translocations and to identify parental chromosome rearrangements
- Deletion/duplication analysis by CMA to detect smaller deletions (i.e., > 5 Mb) or interstitial deletions or complex rearrangements
There are other problems (symptoms) that many individuals with 1p36 deletion syndrome develop:
- About 90% have severe learning disabilities
- About 75% will have no ability to form words, the other approximate 25% will only develop a few words or phrases
- About 70% develop types of heart problems
- About 50% will develop seizures, behavior problems, and hearing problems
- Other problems such as weak muscle tone, breathing problems, eye problems, swallowing problems, genital malformations (usually minor in males), and metabolic problems have been reported