Defect of
long-chain
fatty acid
oxidation
| Avoidance of fasting
Birth-age 3 mos: frequent feeds (every 2-3 hrs) Age 4-12 mos: feeding interval can be ↑ to every 4 hrs if tolerated by 6 mos. From age 6 to 12 mos, daytime feeding interval every 4 hrs; overnight fasting can be gradually ↑ to 6-8 hrs by 12 mos. Age 1-3 yrs: daytime feeding interval 4 hrs; overnight fasting up to 10 hrs may be attempted Age 3+ yrs: overnight fasting up to 12 hrs may be attempted
| ↓ feeding interval by half during periods of illness. After age 1 yr, if preprandial hypoglycemia remains an issue, consider overnight feedings or 1 gm/kg of uncooked cornstarch at bedtime to ensure sufficient glucose supply overnight.
|
| MCT supplementation
| MCT can bypass carnitine shuttle & enter mitochondria directly. As medium-chain fatty acid oxidation is intact, it provides important source of calories & is cornerstone of mgmt in long-chain FAOD. |
Triheptanoin (C7)
Approved by FDA in 2020 for treatment of long-chain FAODs; can be used as an alternative to MCT to provide up to 35% of daily calorie intake. Triheptanoin treatment can ↓ frequency of hospitalizations & rhabdomyolysis 1 & improve cardiomyopathy, hepatomegaly, & hypoglycemia. 2 Adverse effects are mainly gastrointestinal & transient (e.g., abdominal pain, diarrhea).
| Triheptanoin is an odd-chain MCT consisting of 3 7-carbon fatty acids metabolized to acetyl CoA & propionyl CoA. Propionyl CoA provides an anaplerotic effect by replenishing mitochondrial tricarboxylic acid cycle intermediates. Thus, compared to even-chain MCT, triheptanoin provides addl benefits through anaplerosis. 3 |
Secondary
carnitine
deficiency
| L-carnitine: 25-50 mg/kg daily in 3 divided doses | Carnitine supplementation is NOT recommended unless there is carnitine deficiency because of concern for cardiotoxicity of long-chain hydroxyacylcarnitine derivatives. |
Poor weight
gain / FTT
|
| Low threshold for clinical feeding eval &/or radiographic swallowing study if clinical signs or symptoms of dysphagia |
|
DD/ID
| Interventions per developmental pediatrician / neurodevelopment specialist | PT, OT, & speech therapy, as indicated |
Cardiac
dysfunction
| Interventions per cardiologist | Early diagnosis & strict dietary therapy can prevent & even reverse cardiomyopathy. 4 |
Peripheral
neuropathy
| Interventions per neurologist | Early diagnosis & strict dietary therapy may delay onset or slow progression but may not completely prevent this complication. 5 |
|
Retinopathy
| Interventions per ophthalmologist | Early diagnosis & strict dietary therapy may delay onset or slow progression but may not completely prevent this complication. 6 |
