Child with De Novo t(1;6)(p22.1;p22.1) translocation and features of ectodermal dysplasia with hypodontia and developmental delay.

We report on a 6.5-year-old girl with a balanced translocation between the short arms of chromosomes 1 and 6. She was referred for genetics evaluation because of developmental speech delay and congenital absence of several deciduous and permanent teeth. She was very sensitive to noise (hyperacusis), had poor hair and nail growth, decreased sweating, and turned very red with high fever. She had microcephaly (head circumference at the second centile; weight and height were at 25th centile), short palpebral fissures, epicanthal folds, sparse eyelashes, large ears, partial anodontia, short finger and toenails, and dry skin. She had mild developmental delay. Family history was significant for learning problems in two paternal uncles, one paternal aunt, and several paternal cousins. Thyroid studies, calcium, phosphorus, and alkaline phosphatase levels were normal. Her karyotype was 46,XX,t(1;6)(p22.1;p22.2), and parental karyotypes were normal. This apparently balanced translocation may have resulted in either a submicroscopic loss or disruption of a gene or genes involved in ectodermal dysplasia. There are no reported cases of ectodermal dysplasia associated with this chromosome rearrangement.