Chromosome 21q tetrasomy syndrome. Tetrasomy 21q.
Incidence
Very rare syndrome. Sporadic.
Clinical Characteristics
Partial tetrasomy involving the long arm of chromosome 21 with mental retardation, craniofacial dysmorphism, hernia, genital anomalies, and hand and foot deformities.
Precipitants
None
Provocation Tests
None
Diagnostic Procedures
Karyotype. The karyotype is designated as 47,XY,+i(21q).