UNLABELLED: We describe a newborn girl with a life-threatening laryngomalacia and extreme hypotonia. Genetic analysis revealed the very rare genetic condition mosaicism of 48,XXXX and 49,XXXXX (50/50). We here state that the degree of early hypotonia constitutes an important early prognostic feature in this syndrome. The timely insertion of a gastrostomy is warranted in order to prevent aspiration. CONCLUSION: A karyotype is mandatory in female newborns with moderate to severe hypotonia in order to exclude polyploid mosaicism of the X chromosome. An 'overall prognosis' for 48,XXXX and 49,XXXXX girls is difficult to provide towards parents in line with a well-known, substantial variability in outcome for all polysomy X infants.
UNLABELLED: We describe a newborn girl with a life-threatening laryngomalacia and extreme hypotonia. Genetic analysis revealed the very rare genetic condition mosaicism of 48,XXXX and 49,XXXXX (50/50). We here state that the degree of early hypotonia constitutes an important early prognostic feature in this syndrome. The timely insertion of a gastrostomy is warranted in order to prevent aspiration. CONCLUSION: A karyotype is mandatory in female newborns with moderate to severe hypotonia in order to exclude polyploid mosaicism of the X chromosome. An 'overall prognosis' for 48,XXXX and 49,XXXXX girls is difficult to provide towards parents in line with a well-known, substantial variability in outcome for all polysomy X infants.
Authors: O Demirhan; N Tanriverdi; M B Yilmaz; S Kocaturk-Sel; N Inandiklioglu; U Luleyap; E Akbal; G Comertpay; T Tufan; O Dur Journal: Balkan J Med Genet Date: 2015-12-30 Impact factor: 0.519