Clinical Manifestations of Telomere Abnormalities

      The clinical manifestations of telomere abnormalities are variable and can be dependent on the chromosomes involved in the rearrangements, if there is a deletion, duplication, or both, and how large of a piece of the chromosome is involved.  Because this testing is relatively new, and there are many possible telomere rearrangements, there is limited information available about specific telomere abnormalities.  However, because addition or deletion of chromosome material leads to significant problems with growth and development some generalizations can be made. 

1)   Almost all reported patients with a telomere abnormalitythat is associated with their clinical features have some degree of developmental delay or mental retardation. Most appear to fall in the moderate-severe range of delay, however individuals with mild delays have been seen.

2)   Most individuals are often described as having dysmorphic features.  Dysmorphic features are physical characteristics that look different from others, particularly different from the members of an individual?s family.  Examples of facial dysmorphic features include ears that are low set are eyes that are spaced farther apart than normal (hypertelorism).  The specific dysmorphic features seen in a patient with a telomere rearrangement are varied is likely dependent on the specific chromosome material involved.  
 

3)   Birth defects are also very common. Birth defects may also be referred to as congenital anomalies.  Either term is used to describe an abnormality that occurs in a child during the early stages of development that occur before a child is born.  Birth defects can affect any part of the body. Some common examples include cleft lip or palate, congenital heart defects, brain malformations, and limb anomalies.  Children with telomere abnormalities may or may one or a combination of birth defects.

4)   Delayed or poor growth- Babies with telomere abnormalities may not grow well before or after delivery. If inadequate growth occurs before birth this may be called IUGR (intrauterine growth retardation) or SGA (small for gestational age).  Additionally, babies may have a normal birth weight, but experience problems with weight gain or growth as infants and children.  Additionally, head growth may be inadequate resulting in microcephaly (small head size).

      Because telomere rearrangements are relatively rare, multiple labs perform the testing, and because there are so many possible different arrangements, there is limited information available to physicians and families of patients with telomere rearrangements.  In order to allow people to share their experiences and consolidate this information for future use, we have developed an online database to allow physicians and families to submit information regarding their patients with telomere abnormalities.  We hope this information will be useful for physicians to provide better prognostic information to families.

      **************Click here to learn more about database.********************************

      There are published descriptions of a few telomere abnormalities, 1p deletion, 6q deletion, 16p trisomy, and 22q deletion. To learn more about these specific abnormalities and other telomere rearrangements, click here to visit the telomere atlas.