Syndactyly type 9

Alternate names

Syndactyly mesoaxial synostotic with phalangeal reduction; MSSD; Syndactyly Malik-Percin type

Definition

Mesoaxial synostotic syndactyly (MSSD) with phalangeal reduction is a novel and distinct form of non-syndromic syndactyly including complete syndactyly of the 3rd and 4th fingers with synostoses of the corresponding metacarpals and associated single phalanges, syndactyly of the 2nd and 3rd toes and 5th finger clinodactyly.

Epidemiology

It has been described in two families.

Cause

The locus for this complex limb malformation was mapped to chromosome 17p13.3.

Inheritance

Autosomal recessive inheritance, a 25% chance

The condition is transmitted as an autosomal recessive trait.

Signs and symptoms

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

• 2-3 toe syndactyly(Webbed 2nd and 3rd toes)
• Aplasia/Hypoplasia of the middle phalanges of the hand(Absent/small middle finger bone of the hand)
• Clinodactyly of the 5th finger(Permanent curving of the pinkie finger)
• Finger syndactyly
• Metacarpal synostosis(Fused long bones of hand)
• Short hallux(Short big toe)
• Short palm
• Short thumb(Short thumbs)
• Symphalangism affecting the phalanges of the hand(Fused finger bones of the hand)

30%-79% of people have these symptoms

• Synostosis of carpal bones(Fusion of wrist bones)

Diagnosis

An infant with webbing may have other symptoms that together may be signs of one syndrome or condition. That condition is diagnosed based on a family history, medical history, and physical exam.

The following tests may be done:

• Chromosome studies
• Lab tests to check for certain proteins (enzymes) and metabolic problems
• X-rays

Treatment

Surgery may be done to separate the fingers or toes.

NIH genetic and rare disease info

• NIH info on Syndactyly type 9

Syndactyly type 9 is a rare disease.