[Alopecia, deformed ear and mental retardation associated with terminal 21q deletion]

Partial 21q monosomy is a rare condition with only a few cases being described in the literature. We report a new case associating congenital alopecia with 21q deletion.

At birth, a female infant presented with diffuse alopecia, atrichia of the eyelashes and eyebrows, and deformed ears. Her development was marked by the appearance of intellectual deficit. Chromosome analysis by karyotype and CGH (comparative genomic hybridization) array revealed ring chromosome 21 with 21q22.3 terminal deletion of 3.6 Mb. The other laboratory examinations were unremarkable, and simply ruled out the main differential diagnoses. Treatment with zinc and Minoxidil^® 5% allowed regrowth of lightly pigmented down on the scalp alone.

A combination of alopecia, deformed ears and mental retardation should suggest a diagnosis of partial 21q monosomy. Alopecia, which is poorly described in this syndrome, seems to be more frequently associated with 21q22.3 terminal involvement.