Hemihypertrophy (hem′ē-hī-pur′trə-fē)


Hemihypertrophy, also known as hemihyperplasia, is a greater than normal asymmetry between the left and right side of the body.  This asymmetry can include just one finger; just one limb; just the face; or an entire half of the body, including half the tongue, half the brain and the internal organs, or any variation in between.


I have what is known as Complex or Total Hemihypertrophy (hemi).  This means that it involves only one side of the body from the head down.  The hemi affects the entire right side of my body.  We will learn more about how this will affect my growing after we see the geneticist in October.


The cause of hemihypertrophy is not known.  However, it has been found that hemihypertrophy is usually not inherited.  Hemi is thought to occur in about 1 in 14,000 people.  Isolated hemihypertrophy occurs in about one in 86,000 live births.  There are approximately 200 cases reported.  Females and males are affected equally.  Some children with hemihypertrophy also have a genetic syndrome, such as Beckwith-Wiedemann syndrome, neurofibromatosis, Klippel-Trenaunay-Weber syndrome, CMTC(Cutis marmorata talengiectatica congenita), or Proteus syndrome.  Inguinal hernias, undescended testicles, and unusual kidneys (renal cysts or horseshoe-shaped kidneys) are more common in children with hemihypertrophy whether or not they have other syndromes. 
A general guideline for identifying hemihypertrophy is: a 5% or greater difference in size or length between some aspect of the right and left sides of the body.  This translates into a leg-length difference of about 1/2 inch for a 1-year-old, about 1 inch for a 5-year-old, and about 1-1/2 inches for an adult.  As children with hemihypertrophy grow, the discrepancy between the two sides increases, but the relative proportions between the two sides usually remains the same over the long haul.  Variations are found among different children, but in most children, the discrepancy about doubles between the first and fifth birthdays.


Because hemihypertrophy is a disorder of the body's normal controls of growth, people with this condition also have a higher rate of cancer.  The most common cancer is Wilms' Tumor (of the kidney), followed by adrenal carcinoma and liver cancer (hepatoblastoma).  Because most of the cancers occur in the abdomen, the recommendation has been made that children with hemihypertrophy receive a screening abdominal ultrasound every 3 months until age 8, and, at minimum, a careful physical examination every 6 months until growth is completed.  AFP (alpha fetoprotein) levels may also be useful as a marker of hepatic tumors.  The AFP testing should be done every 6 weeks until age 4.


The next most immediate concerns are the orthopedic problems that result from any leg-length discrepancy.  Over time, scoliosis, or curvature of the spine, commonly develops.  This disappears when the leg lengths are equalized, either with surgery or with special shoes or lifts.


Hemihypertrophy does not alter life span, although complications from associated abnormalities such as childhood cancer and mental retardation can cause problems.  Asymmetry of the limbs can interfere with their proper function and cause pain.  Insecurities due to disfigurement are possible and can be addressed through support groups or therapy.


Limb Length Discrepancy (LLD)

The link below gives information on Limb Length Discrepancy through identification, monitoring, problems caused by LLD and procedures for correcting it.  LLD is caused by hemihypertrophy and is something we may have to deal with in the future.