People who have TANGO2 deficiency are missing the TANGO2 protein from birth so often present early in childhood. There are a variety of issues caused by the missing protein and how people are affected is variable.
Common key presentations are…
Metabolic crisis – this is when the body is unable to access energy due to the missing protein. This is much more likely to occur when a child is unwell (and has increased energy needs) or when fasting (so not taking regular energy supplies like overnight). Metabolic crisis means the body shuts down and there can be huge injury caused to the brain/ heart/ muscles/ kidneys. Unfortunately, the body often cannot recover fully from the injury, and it may leave long term significant disability. In the case of TANGO2 there are specific heart rhythm irregularities that can occur which means that any child in crisis needs to be closely watched as this is life threatening.
TANGO2 spells (slurring/ droopy eyelids/ ataxia/ wobbly walking and veering – often misdiagnosed these funny turns can be misinterpreted as seizures or weakness. These episodes seem to increase in frequency around the age of 2y and puberty. Triggered also by fatigue or illness or stress. B group Vitamins have so far shown good evidence to help reduce and even stop these episodes.
Learning difficulties – children are often found to have a degree of global delay.
Spasticity and Toe Walking – a proportion of children require splints or botox for tight muscles (hypertonicity) and toe walking is common.
Speech and swallowing disturbance – unusual slurring or nasal speech can be found during and outside of TANGO2 spells. Some children are also found to have reduced soft palate movements and drooling is not uncommon
Hypothyroidism – it is unclear why this is often concurrently diagnosed but a significant proportion of TANGO2 affected individuals also require thyroxine treatment.
Epilepsy– in some cases this may be secondary to metabolic crisis and brain damage but there are also links with epilepsy disorders irrespective of crisis history and a higher chance of developing Epilepsy in the future.
DonateHow can individuals be diagnosed with TANGO2?
Most affected individuals will present in either crisis or unwell or at a young age with problems walking and talking and developmental delay. There are some distinguishing features to TANGO2 presentation which may help a clinician recognize it such as the unusual gait. However, diagnosis can only be confirmed by genetic testing. Due to its rarity this can take many years before it is identified.
