Silver Russell Syndrome

Klinische Symptomatik

The Silver-Russell syndrome is characterized by pre- and postnatal dwarfism with macrocephaly relative to body size. At birth, body size is on average 43 cm and body weight approx. 1900 g.

Typical craniofacial features include broad prominent forehead with a small triangular face and a small narrow chin. Stature remains small after birth and 50% of the patients develop some kind of body asymmetry. Affected children are gracile, often have a small thorax and frequently muscular hypotonia. Most patients show normal mental development, however, there is a risk of usually mild developmental delay (both motor and cognitive).

Genetik

Silver-Russel syndrome is a genetically heterogeneous condition. About 10% of the cases are caused by maternal uniparental disomy for chromosome 7 (UPD7 mat). Symptoms are caused by the absence of paternally contributed genes on chromosome 7.

Mostly, the Silver-Russell is of sporadic nature; however, families with autosomal dominant, autosomal recessive and X-linked inheritance have been described. In single cases, structural abnormalities of chromosomes were detected in Silver-Russell patients. The recurrence risk in case of a maternal UPD 7 is below 1%.

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Diagnostik