We read with interest the review article by Dr. Crolla [1998] which stated that supernumerary marker chromosomes from all the human autosomes except chromosome 5 have been reported. We therefore describe a patient with a supernumerary ring chromosome 5.
The patient, a boy, was the only child of healthy, nonconsanguineous Japanese parents, both age 31 at the time of his birth. The patient was born at 39 weeks of gestation: He weighed 2,540 g (-1.7 SD), his length was 47.6 cm (-1.1 SD), and his OFC was 32.8 cm (-0.5 SD). He had congenital stridor due to laryngomalacia, and telecanthus, low nasal bridge, hypoplastic columella, preauricular tag, and high-arched palate. He sat alone at age 8 months and walked at 17 months. He twice had febrile convulsions. Computed tomography of the brain was normal as were fundi. At age 3 2/12 years, his height was 97.4 cm (+0.8 SD), weight was 15.7 kg (+0.9 SD), and OFC was 50.5 cm (+0.5 SD). He spoke no meaningful words.
The patient had a mosaic supernumerary ring chromosome with GTG banding from peripheral lymphocyte culture (Fig. ). The ring chromosome was negative for both NOR and distamycin A/DAPI staining. The chromosomes of the parents were normal.
Stepwise FISH analysis of the ring chromosome was performed using whole chromosome paint probes (Oncor) numbers 2, 4, 5, 7, 8, 10, 11, 12, 17, and 20 until the chromosomal assignment was made. The ring was identified as 5 using the whole chromosome paint 5 and the alpha-satellite probe for chromosomes 1/5/19. His karyotype was thus 47,XY,+mar de novo[24]/ 46,XY [26].ish r(5)(wcp5+,D1Z7/D5Z2/D19Z3+).
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