Partial trisomy of chromosome 3 (3q12 leads to qter) owing to 3q/18p translocation. A trisomy 3q syndrome.

In four previously reported patients with partial 3q trisomy, only a small portion of 3q was trisomic (3q21 leads to qter or 3q25 leads to qter). Clinical features in these cases have included the following: low-set ears, mongoloid slant of eyes, hypertelorism, cleft palate, webbed neck, simian creases, short finger, clinodactyly, hypotonia, and low-set hairline. Cytogenetic studies of a premature, 1,680-g female infant with with these clinical features showed this extra material to be part of the long arm of chromosome 3 (3q12 leads qter), which resulted in partial trisomy for this segment, ie, 46,XX,-18, +t (3;18) (q12;p11). Although a larger portion of 3q was involved in this case, the clinical picture was similar to other cases of 3q duplication with or without 3p deletion.