Split hand foot malformation

Alternate names

SHFM; Ectrodactyly

Definition

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.

Summary

• 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.
• The severity of this condition varies widely among affected individuals.

Forms

• 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.

Cause

• 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.

Inheritance

SHFM may be inherited in an autosomal dominant, autosomal recessive, or X-linked manner.

Clinical presentation

For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. 80%-99% of people have these symptoms

• Oligodactyly

30%-79% of people have these symptoms

• Finger syndactyly

5%-29% of people have these symptoms

• Absent hand
• Aniridia(Absent iris)
• Sensorineural hearing impairment
• Split hand(Claw hand)

NIH genetic and rare disease info

• NIH info on Split hand foot malformation

Split hand foot malformation is a rare disease.