We report a male infant with a 47,XY, + der(22),t(1;22)(q32;q11)pat karyotype. Thus, he has duplication of chromosomes 1(q32----qter) and 22(pter----q11). Six patients with dup 1(q32----qter) and eight with dup 1(q42----qter) have been described. These two groups of patients share several manifestations, including postnatal growth retardation; relative
macrocephaly with widely separated
sutures or large fontanelles; prominent forehead; highly arched palate;
micrognathia; downward slant of the palpebral fissures; broad, flat nasal bridge; and apparently low-set, malformed ears. Although many of these abnormalities are nonspecific, partial duplication of 1q should be considered in infants with relative
macrocephaly, large fontanelles, and downward slant of the palpebral fissures. Our patient had duplication of the part of chromosome 22 that may be associated with the clinically variable
cat-eye syndrome. Patients with dup 22(pter----q11) may also have downward slant of the palpebral fissures,
micrognathia, and apparently low-set, malformed ears. The structural gene locus for
beta-glucosidase has been mapped to chromosome 1.
beta-Glucosidase activity in fibroblasts from our patient was normal, and his parents' activities were not significantly different from those of control individuals. Therefore, either the locus for this
enzyme is not present on 1(q32----qter) or the
enzyme does not consistently show a substantial gene-dose effect.