Hemihyperplasia

Question 1

What is hemihyperplasia?

Answer 1

congenital asymmetrical overgrowth associated with embryonic tumors including Wilm’s tumor and hepatoblastoma. Patients should have abdominal ultrasounds until the age of 7 and AFP levels measured until the age of 4 to monitor possible growth of abdominal tumors, these screenings should be performed every 3 months.

Question 2

What is a similar genetic disorder to isolated hemihyperplasia?

Answer 2

Beckwith-Weiderman Syndrome

Question 3

How can you differentiate between BWS and Isolated Hemihyperplasia?

Answer 3

There is no identified single gene for IH, therefore molecular studies are unhelpful. Tumor studies should be done in patients at risk.

occaisionally patients are found to have a mutation, this is not the majority of IH patients. 70% of patients with BWS will have an epigenetic or genetic finding.

Question 4

Other overgrowth syndromes

Answer 4

NF1, BWS, Mosaic trisomy 8, proteus syndrome, plus disorders associated with vascular malformations

Question 5

possible genetic findings in isolated hemihyperplasia

Answer 5

Loss of maternal methylation, UPD and hypermethylation

Question 6

Tumors and isolated hemihyperplasia

Answer 6

Incidence is roughly 6%. Many of these tumors are embryonal with the vast majority of them identified as Wilm’s tumors, hepatoblastomas, and adrenal cell carcinomas. The majority are seen in the abdomen, though they can be seen in other parts of the body.

Question 7

What is Wilm’s tumor?

Answer 7

A malignant tumor of the kidney, of a type that occurs in young children.