Table 1.

Summary of clinical features, DHRSX variants, and serum Tf IEF results of the four patients

	Patient 1	Patient 2	Patient 3	Patient 4
Age	7 years	11 months (✝)	6 years	4 years
Sex	female	female	male	male
DHRSX variant (NM_145177.3)	c.541G>T; p.(Val181Phe)	c.146C>T; p.(Thr49Met)	c.541G>T; p.(Val181Phe), c.643C>T; p.(Leu215Phe)	c.541G>T; p.(Val181Phe), c.643C>T; p.(Leu215Phe)
Facial dysmorphism	a	a	a	a
Neurological findings
Developmental/intellectual disability	severe	severe	severe	severe
Epilepsy	–	a	a	a
Axial hypotonia	a	a	a	a
Bilateral sensorineural hearing loss	profound	auditory evoked potentials inconclusive	profound	profound
Brain MRI	bilateral hypoplasia of cranial nerves V, VII and VIII	small corpus callosum	mild thinning of corpus callosum; bilateral absence of the cochlear nerves; superior and inferior vestibular nerves bilaterally absent/hypoplastic	bilateral absence of the cochlear nerves, superior and inferior vestibular nerves bilaterally absent/hypoplastic
Ophthalmological findings	bilateral neurotrophic keratopathy	normal	bilateral neurotrophic keratopathy	corneal erosion of the right eye
Gastrointestinal findings
Failure to thrive	a	a	a	a
Tube feeding	gastrostomy	gastrostomy	gastrostomy	gastrostomy
Hepato(spleno)megaly	hepatosplenomegaly in infancy	cholestasis; hepatomegaly	absent	absent
Other	obstipation		gastroesophageal reflux disease	gastroesophageal reflux disease
Dermatological findings	hypertrichosis of arms and legs	ichthyosis	eczema	–
Other findings	severe apnea episodes; contractures of elbows and knees	persistent ductus arteriosus	stridor; severe obstructive sleep apnea requiring BiPAP; scoliosis; knee contractures	stridor; respiratory insufficiency requiring BiPAP; scoliosis knee contractures
Serum transferrin isoelectrofocusing	type 1	mild type 1	type 1 up to 1 year	normal

^apresent.