Thin Ribs on Chest X-Ray—a Sign Pointing the Way to the Diagnosis of Congenital Myotonic Dystrophy
Delivery of a full-term eutrophic neonate took place in the setting of prenatal polyhydramnios in a subjectively symptom-free primigravida. Due to pronounced respiratory distress, the neonate needed to be intubated and mechanically ventilated on the intensive care unit. Mechanical ventilation was required for 6 days. In addition, the infant exhibited pronounced muscular hypotonia (“floppy infant”) and very poor feeding, with prolonged weaning from tube feeding over 6 weeks. Furthermore, a chest radiograph showed thin gracile ribs (Figure), prompting suspicion of a (neuro-)muscular disease. Clinical examination of the child’s mother, who exhibited abnormal facies, revealed grip myotonia during handshake. This strengthened the suspicion of congenital myotonic dystrophy type 1 (DM1) in the newborn. Autosomal dominant congenital DM1 is due to a CTG repeat expansion of the DMPK (dystrophia myotonica protein kinase) gene on chromosome 19q13.32. Molecular genetic testing of the infant revealed pathological expansion (>> 1000 CTG units), thereby confirming the suspected diagnosis. In view of the syndromic nature of the disease, the infant was referred to a social pediatric center.
Jana Hiekel, Dr. med. Maxi Kaufmann, PD Dr. med. Jürgen Dinger, Fachbereich Neonatologie, Klinik und Poliklinik für Kinder und Jugendmedizin, Medizinische Fakultät Carl Gustav Carus, TU Dresden; Maxi.Kaufmann@uniklinikum-dresden.de
Conflict of interest statement: The authors state that no conflict of interest exists.
Translated from the original German by Christine Rye.
Cite this as: Hiekel J, Kaufmann M, Dinger J: Thin ribs on chest X-ray—a sign pointing the way to the diagnosis of congenital myotonic dystrophy. Dtsch Arztebl Int 2022; 119: 305. DOI: 10.3238/arztebl.m2022.0029