[MIM 249 270]

English acronym for Thiamine Responsive Megaloblastic Anemia

Very rare: less than 80 published cases. Autosomal recessive transmission of a mutation of the SLC19A2 gene (1q23.3) coding for a high affinity carrier of thiamin. It probably results in a deficiency in thiamine pyrophosphokinase (see this term).

Clinical presentation:

-        onset in early childhood and adolescence

-        causes the triad (phenotype close to Wolfram syndrome or DIDMOAD):

♦        megaloblastic anemia with neutropenia and thrombocytopenia, responding to daily thiamine administration

♦        diabetes mellitus (non-type I)

♦        deafness and or optic atrophy (retinal dystrophy and optic nerve atrophy)

-        sometimes: hand and foot paresthesia, short stature

-        sometimes: congenital heart disease (ASD or VSD) and rhythm or conduction disorders, cerebral strokes

Diagnosis: bone marrow shows megaloblastic anemia associated with erythroblasts containing iron-filled mitochondria (ringed sideroblasts).

Treatment: high daily doses of thiamin (vitamin B1, 25-75 mg per day) to reduce anemia and improve if possible, the progression of diabetes mellitus .

Anesthetic implications:

check hemoglobin and blood platelets levels, ECG and echocardiography, diabetes control, hearing-impaired patient, management of a mitochondrial cytopathy

References :

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Updated: May 2021