Association of ring chromosome 18 and Prader-Willi syndrome: the first described case report

Ring chromosome 18 is a rare chromosomal disorder, and its association with Prader-Willi syndrome (PWS) is an extremely unusual condition. We described the clinical and biological profile of this association and highlighted the management of this case through GH therapy. To the best of our knowledge, this is the first reported association in the literature.

This report discusses a case of a 9-year-old child diagnosed with both PWS and ring 18 syndrome at the age of 3 years. The diagnosis of Prader-Willi syndrome with ring chromosome 18 was established using CGH ARRAY technique. It showed the absence of expression of paternal chromosome 15 in the 15q11-q13 region, and a karyotype showing ring chromosome 18 according to the formula: 46. XX (37)/46. XX r(18) (p11.3 ;q23) (27).

Our case contributes to a better understanding of the clinical presentation of complex aberrations of chromosome 18 and that of PWS. The main common clinical features of this association were a moderate dysmorphic syndrome, hypotonia, grade II obesity with severe OSA, mild cognitive deficit with learning difficulties, and a discreet scoliosis. Diagnosis and management of this complex disorder require a multidisciplinary approach. The primary focus for those patients is to enhance their quality of life and prevent any potential complications.