Mutations in SLC25A19 can result in 2 syndromes - Thiamine Metabolism Dysfunction Type 4 and Microcephaly of the Amish type.
Chromosome location: 17q25.1
Gene: SLC25A19
Product: mitochondrial thiamine pyrophosphate carrier
Inheritance: autosomal recessive
Features of Amish Lethal Microcephaly:
(1) severe congenital microcephaly
(2) severe 2-ketoglutaric aciduria
(3) death during infancy, often with metabolic acidosis due a viral illness
Features of Thiamine Metabolism Dysfunction Type 4:
(1) normal head circumference at birth with normal early childhood development
(2) onset of recurrent encephalopathy during childhood
(3) chronic progressive polyneuropathy with flaccid paralysis and dystonia
(4) bilateral striatal necrosis
(5) clinical response to thiamine
