CHONDRODYSPLASIA PUNCTATA - A BOY WITH X-LINKED RECESSIVE CHONDRODYSPLASIA PUNCTATA DUE TO AN INHERITED X-Y TRANSLOCATION WITH A CURRENT CLASSIFICATION OF THESE DISORDERS

Chondrodysplasia punctata (CDP) is a heterogeneous group of rare bone dysplasias characterized by punctate calcification of cartilage. The punctate calcifications are non-specific and have been seen in a wide variety of disorders including the Zellweger syndrome, warfarin, dilantin, alcohol and rubella embryopathies, vitamin-K-epoxide-reductase deficiency, chromosome trisomies 18 and 21, the Smith-Lemli-Opitz syndrome, prenatal infectious chondritis, hypothyroidism, and other rare disorders. We report on a boy with short stature, developmental delay, na. sal hypoplasia, telebrachydactyly, hypoplastic genitalia, CDP, ichthyosis, hypoplastic genitalia, and a 46 - X, + der(X),t(X;Y)(p22.3 1; q11.21), Y karyotype. Genomic DNA probe analysis was interpreted as showing that the translocation breakpoint was within the X-linked Kallmann syndrome gene. We review a current classification of these disorders that includes 3 well-defined single gene disorders. These include an autosomal recessive rhizomelic type with early lethality, an X-linked dominant type with presumed male lethality, and an X-linked recessive type that has only been described as part of a contiguous gene deletion syndrome.