| Note | Usually hemihypertrophy occurs sporadically but familial cases are reported. Though molecular defects have not been identified in all cases, there is evidence that IH occurs due to epigenetic defects or paternal uniparental disomy of genes of 11p15 in somatic mosaic form. |
| Phenotype and clinics | Cases with hemihypertrophy not fulfilling criteria of complicated hemihypertrophies are grouped under isolated hemihypertrophy or hemihyperplasia. Though the title included the word 'hemi', only one limb may be involved. The condition is usually nonprogressive and the body disproportion does not change. Bone age may or may not be increased on the hypertrophied side. Some cases of isolated hemihyperplasia have other features like naevi, capillary haemangiomas and hypertrichosis. Mental retardation may be present. There are no specific laboratory abnormalities. Viscera (kidney) on the hypertrophied side may be enlarged. Plexiform neurofibromas may look like hemihypertrophy. |
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| | A child with isolated hemihypertrophy involving left lower limb. Note Poland anomaly and hypoplastic nipple on left side - a rare associated feature. |
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| Neoplastic risk | The risk of neoplasm is around 5%. Wilms tumour is the commonest; but other tumors like hepatoblastoma, adrenal cell tumour and leiomyosarcoma are also reported. Three monthly ultrasonographic follow up for Wilms tumour up to 5 years and then yearly up to the completion of growth is recommended. |
| Treatment | Usually limb discrepancy is mild and no treatment is required. Corrective shoes, orthopedic procedures may be needed to correct limb length discrepancy. Evaluation of cognitive function and appropriate training may be needed. |
| Prognosis | The condition is nonprogressive and the prognosis is good. Close follow up for early detection of Wilms tumour is needed. |
| Clinical differentiation between Proteus syndrome and hemihyperplasia: description of a distinct form of hemihyperplasia. |
| Biesecker LG, Peters KF, Darling TN, Choyke P, Hill S, Schimke N, Cunningham M, Meltzer P, Cohen MM Jr |
| American journal of medical genetics. 1998 ; 79 (4) : 311-318. |
| PMID 9781913 |
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| Isolated hemihyperplasia (hemihypertrophy): report of a prospective multicenter study of the incidence of neoplasia and review. |
| Hoyme HE, Seaver LH, Jones KL, Procopio F, Crooks W, Feingold M |
| American journal of medical genetics. 1998 ; 79 (4) : 274-278. |
| PMID 9781907 |
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| LIT1 and H19 methylation defects in isolated hemihyperplasia. |
| Martin RA, Grange DK, Zehnbauer B, Debaun MR |
| American journal of medical genetics. Part A. 2005 ; 134 (2) : 129-131. |
| PMID 15651076 |
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| Children with idiopathic hemihypertrophy and beckwith-wiedemann syndrome have different constitutional epigenotypes associated with wilms tumor. |
| Niemitz EL, Feinberg AP, Brandenburg SA, Grundy PE, DeBaun MR |
| American journal of human genetics. 2005 ; 77 (5) : 887-891. |
| PMID 16252245 |
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| Constitutional UPD for chromosome 11p15 in individuals with isolated hemihyperplasia is associated with high tumor risk and occurs following assisted reproductive technologies. |
| Shuman C, Smith AC, Steele L, Ray PN, Clericuzio C, Zackai E, Parisi MA, Meadows AT, Kelly T, Tichauer D, Squire JA, Sadowski P, Weksberg R |
| American journal of medical genetics. Part A. 2006 ; 140 (14) : 1497-1503. |
| PMID 16770802 |
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| Paternal uniparental disomy in monozygotic twins discordant for hemihypertrophy. |
| West PM, Love DR, Stapleton PM, Winship IM |
| Journal of medical genetics. 2003 ; 40 (3) : 223-226. |
| PMID 12624145 |
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