An adult Chinese patient with developmental delay with short stature, dysmorphic features, and sparse hair (Loucks-Innes syndrome).

Variants of the diphthamide biosynthesis I (DPH1, OMIM*603527) are associated with developmental delay, short stature, and sparse hair syndrome (DEDSSH/DPH1 syndrome) (OMIM# 616901). Another name is Loucks-Innes syndrome. DPH1 syndrome is an ultrarare and severe neurodevelopmental disorder. Less than 20 patients were reported from different ethnicities. Here, we described the first Chinese adult with genetically confirmed DPH1 syndrome. We summarized previously reported patients in the literature and found that developmental delay, unusual skull shape, sparse hair, and facial dysmorphism were consistently present in all DPH1 syndrome patients. Dysplastic toenails and dental abnormalities are age-dependent characteristics of DPH1 syndrome. Our patient was the first reported patient with documented growth hormone deficiency. Dental and endocrine checkup should be considered in the routine follow-up of DPH1 syndrome patients.