Clinical features and respiratory complications in Myhre syndrome

We describe the clinical characteristics of 4 singleton cases, 3 males and 1 female, with Myhre Syndrome (OMIM 139210), who were born to non-consanguineous parents. Three cases had no family history of similarly affected individuals but 1 male's mother had short stature, some facial features suggestive of Myhre syndrome and evidence of skewed X-chromosome inactivation in her blood DNA. Short stature, deafness, learning difficulties, skeletal anomalies and facial dysmorphisms were evident in all cases. Arthralgia and stiff joints with limited movement were also present. The facial appearance, thickened skin, a 'muscular' habitus are memorable features. The female patient was least affected: this patient and one affected male displayed streaky skin with areas of patchy thickening, suggestive of genetic mosaicism. One patient developed sleep apnoea, a restrictive ventilatory defect and died following a choking episode. Another affected male developed recurrent, progressive, proximal, tracheal stenosis requiring partial tracheal resection, laser treatment and eventually tracheotomy. Review of Myhre syndrome patients in the literature and syndromes in the differential diagnosis, suggests heterogeneity in Myhre syndrome and clinical overlap with Laryngotracheal stenosis, Arthropathy, Prognathism and Short stature syndrome.