A autosomal recessive disorder caused by mutation in SLC19A2 gene and characterized by megaloblastic anemia, diabetes mellitus and sensorineural hearing loss. This child responds to which nutrient
Vitamin B12
Vitamin c
Vitamin B1
Folic acid
This is Thiamine Responsive Megaloblastic syndrome:

It occurs due to mutation of SLC19A2 gene, encoding thiamine transporter protein, Leading to abnormal thiamine transportation.

Clinical features:

Megaloblastic anemia
Diabetes mellitus
Sensorineural hearing loss.