Trisomy 8 syndrome, with or without mosaicism, is characterized by the following clinical signs and symptoms: mental retardation, deformed skull, prominent forehad, high-arched palate, low-set and/or dysplastic ears, long and slender trunk, reduced joint mobility, and deep plantar furrows. The deep furrow or longitudinal crease of the sole may be pathognomonic for the syndrome. It should be noted that it has been seen in other rare syndromes. It is recommended that a child with mental retardation and associated multiple anomalies should be subjected to a cytogenetic study in order to define the incidence of this syndrome. Differnetial diagnosis should include: Fong's syndrome, arthrogryposis and otopalato-digital syndrome. It is interesting to note that there seem to be individuals who have had no physical abnormalities and have been identified during an evaluation for repeated abortions. The above described case of trisomy 8 mosaicism was seen and treated for many years by many different specialists without an accurate diagnosis.