The middle phalanx in Poland syndrome

Area of Science:

• Orthopedics
• Embryology
• Genetics

Background:

• Poland syndrome is a congenital condition characterized by chest muscle asymmetry and limb malformations.
• Hand abnormalities in Poland syndrome often include syndactyly and brachydactyly.
• The specific role of phalangeal abnormalities in Poland syndrome remains incompletely understood.

Purpose of the Study:

• To investigate and classify the abnormalities of the middle phalanx in patients with Poland syndrome.
• To correlate the degree of middle phalanx deficiency with hand hypoplasia and brachydactyly.
• To explore the potential embryological basis for these phalangeal abnormalities.

Main Methods:

• Radiographic analysis of 15 patients diagnosed with Poland syndrome.
• Classification of hand hypoplasia and brachydactyly into mild, moderate, and severe grades.
• Detailed documentation of radiological features of the middle phalanges.

Main Results:

• All 15 patients exhibited abnormalities in the middle phalanges of their affected hands.
• The severity of middle phalanx deficiency (hypoplasia to aplasia) correlated directly with brachydactyly and overall hand hypoplasia.
• Specific radiological findings included central nidus, rounded/truncated appearance, and cone-shaped epiphyses of the middle phalanges.

Conclusions:

• Middle phalanx abnormalities are a consistent feature in Poland syndrome, correlating with clinical severity.
• These findings suggest a potential link between middle phalanx development and limb hypoplasia in Poland syndrome.
• A mild ischemic insult during embryonic stage 19 is proposed as the cause of defective chondrification leading to these phalangeal abnormalities.