Because of her missing sucking reflex, feeding was difficult and she developed a severe malnutrition necessitating gastric tube feeding. Furthermore, the patient developed a duodeno-gastro-esophageal reflux disease (Table 1).
Patient II died at the age of 14 months due to a bronchopulmonary infection in the course of which she developed a rapidly decreasing oxygen saturation and an increasing bradycardia.
Whole exome sequencing of patients I and II revealed the homozygous stop mutation c.6016C>T (p.R2006*protein with 2564 aa, Mut. Ex 28 of 36) in the SPTBN4 gene in both patients. Homozygous carrier status was confirmed by Sanger sequencing in both patients.
Heterozygous carrier status of the mother and the healthy sister was confirmed by Sanger sequencing as well.
DNA of the father has been unavailable.