What are the other Names for this Condition? (Also known as/Synonyms)

• Ectrodactyly
• SHFM (Split Hand Foot Malformation)

What is Split Hand Foot Malformation? (Definition/Background Information)

• Split Hand Foot Malformation (SHFM) is a type of birth defect that consists of missing digits (fingers and/or toes), a deep cleft down the center of the hand or foot, and fusion of remaining digits
• The severity of this condition varies widely among affected individuals. SHFM is sometimes called Ectrodactyly; however, this is a nonspecific term used to describe missing digits
• SHFM may occur by itself (isolated) or it may be part of a syndrome with abnormalities in other parts of the body. At least six different forms of isolated SHFM have been described. Each type is associated with a different underlying genetic cause
  • SHFM1 has been linked to chromosome 7, and SHFM2 is linked to the X chromosome
  • SHFM3 is caused by a duplication of chromosome 10 at position 10q24
  • Changes (mutations) in the TP63 gene cause SHFM4
  • SHFM5 is linked to chromosome 2, and SHFM6 is caused by mutations in the WNT10B gene
• SHFM may be inherited in an autosomal dominant, autosomal recessive, or X-linked manner

(Source: Split Hand Foot Malformation; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

Who gets Split Hand Foot Malformation? (Age and Sex Distribution)

• Split Hand Foot Malformation is a rare congenital disorder. The presentation of symptoms may occur at birth
• Both males and females may be affected
• Worldwide, individuals of all racial and ethnic groups may be affected

What are the Risk Factors for Split Hand Foot Malformation? (Predisposing Factors)

• A positive family history may be an important risk factor, since Split Hand Foot Malformation can be inherited
• The condition may be seen as part of other genetic disorders (syndromes)
• Currently, no other risk factors have been clearly identified for SHFM

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Split Hand Foot Malformation? (Etiology)

Split Hand Foot Malformation may occur as an isolated feature or it may be associated with a genetic syndrome.

• Researchers believe that a large number of mutations can cause Split Hand Foot Malformation. A few of which have been identified: FBXW4 and TP63
• Most commonly the conditions are passed through families in an autosomal dominant fashion with reduced penetrance
• In autosomal dominant inheritance an affected parent would have a 1 in 2 or 50% chance with each pregnancy of passing the genetic defect to his/her offspring. In conditions with “reduced penetrance” a person who inherits the underlying genetic defect, may never develop the condition
• More rarely other forms of inheritance have been reported (e.g., autosomal-recessive, X-linked, chromosome deletions, chromosome duplications)

(Source: Split Hand Foot Malformation; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

What are the Signs and Symptoms of Split Hand Foot Malformation?

The signs and symptoms of Split Hand Foot Malformation may include:

• Aplasia/hypoplasia involving the metacarpal bones
• Aplasia/hypoplasia of metatarsal bones
• Aplasia/hypoplasia of the phalanges of the hand
• Aplasia/hypoplasia of the phalanges of the toes
• Broad hallux
• Camptodactyly
• Clinodactyly
• Finger syndactyly
• High palate
• Microretrognathia
• Myopia
• Nail dystrophy
• Narrow mouth
• Renal hypoplasia
• Ridged nail
• Short metacarpal
• Short phalanx of finger
• Split foot
• Split hand
• Toe syndactyly
• Triphalangeal thumb
• Variable expressivity

Based on the frequency of symptoms observed, the following information may be noted:

• Very frequently present symptoms in 80-99% of the cases: Oligodactyly
• Frequently present symptoms in 30-79% of the cases:
  • Foot oligodactyly 
  • Hand oligodactyly
  • Syndactyly
• Occasionally present symptoms in 5-29% of the cases:
  • Absent hand 
  • Aniridia 
  • Hypoplasia of the maxilla

(Source: Split Hand Foot Malformation; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

How is Split Hand Foot Malformation Diagnosed?

Split Hand Foot Malformation is diagnosed on the basis of the following information:

• Complete physical examination
• Thorough medical history evaluation
• Assessment of signs and symptoms
• Laboratory tests
• Imaging studies
• Biopsy studies, if necessary

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Split Hand Foot Malformation?

The complications of Split Hand Foot Malformation may include:

• Severe limb deformities in some cases
• Dental abnormalities

Complications may occur with or without treatment, and in some cases, due to treatment also.

How is Split Hand Foot Malformation Treated?

There is no cure for Split Hand Foot Malformation, since it is a genetic condition. The treatment is usually given to manage the signs and symptoms and any complications that develops.

How can Split Hand Foot Malformation be Prevented?

Currently, Split Hand Foot Malformation may not be preventable, since it is a genetic disorder.

• Genetic testing of the expecting parents (and related family members) and prenatal diagnosis (molecular testing of the fetus during pregnancy) may help in understanding the risks better during pregnancy
• If there is a family history of the condition, then genetic counseling will help assess risks, before planning for a child
• Active research is currently being performed to explore the possibilities for treatment and prevention of inherited and acquired genetic disorders

Regular medical screening at periodic intervals with tests and physical examinations are recommended.

What is the Prognosis of Split Hand Foot Malformation? (Outcomes/Resolutions)

• The prognosis of Split Hand Foot Malformation is dependent upon the severity of the signs and symptoms and associated complications, if any
• Individuals with mild conditions have better prognosis than those with severe symptoms and complications
• Typically, the prognosis may be assessed on a case-by-case basis

Additional and Relevant Useful Information for Split Hand Foot Malformation:

The following DoveMed website link is a useful resource for additional information:

http://www.dovemed.com/diseases-conditions/rare-disorders/