A peroxisomal disorder where very-long-chain fatty acid accumulation destroys the adrenal glands and myelin — creating a weight management picture dominated by adrenal insufficiency, neurological decline, and cortisol dependence
X-linked Adrenoleukodystrophy (X-ALD) is a rare peroxisomal disorder caused by mutations in the ABCD1 gene, which encodes the ALD protein — a transporter that moves very-long-chain fatty acids (VLCFAs, carbon chains longer than C22) into peroxisomes for beta-oxidation. When this transporter is deficient, VLCFAs accumulate in plasma and tissues, with particularly damaging effects in the adrenal cortex, the myelin sheaths of the central nervous system, and the spinal cord.
X-ALD is X-linked, meaning it primarily affects males. Females who are carriers may develop milder symptoms, particularly the spinal cord form. The condition has several distinct clinical presentations:
This article focuses on weight management in adult males with AMN or ALD-related Addison disease — the group where diet and lifestyle questions are most relevant.
VLCFA accumulation destroys the adrenal cortex in the majority of males with X-ALD, causing primary adrenal insufficiency (Addison disease). Without cortisol and, in some cases, aldosterone, the body cannot regulate blood sugar, blood pressure, sodium balance, or the stress response. The hallmarks are profound fatigue, weight loss, hypotension, salt craving, hyperpigmentation (bronze skin), nausea, and hypoglycaemia.
Adrenal insufficiency is treated with lifelong hydrocortisone replacement (typically 15-25 mg daily in divided doses, mimicking the natural diurnal cortisol rhythm) and often fludrocortisone (a mineralocorticoid to retain sodium and maintain blood pressure). Once cortisol replacement is optimised, most patients stabilise — but the balance is delicate.
Hydrocortisone at physiological replacement doses does not inherently cause weight gain when dosed correctly. However, over-replacement — taking too much cortisol — promotes visceral fat accumulation, insulin resistance, muscle wasting, and a Cushing-like appearance. Under-replacement causes fatigue, loss of appetite, and weight loss. Getting the dose right, in consultation with your endocrinologist, is the single most important step for stable weight management.
Timing of cortisol doses matters for energy and activity:
Lorenzo's Oil — a 4:1 mixture of glyceryl trioleate and glyceryl trierucate (oleic acid and erucic acid) — was developed in the 1980s by the parents of Lorenzo Odone, a boy with ALD. When taken as approximately 20% of daily calorie intake alongside a diet restricted in saturated VLCFAs, Lorenzo's Oil normalises plasma VLCFA levels in most patients.
Critically, Lorenzo's Oil does NOT reverse existing neurological damage and has NOT been shown to halt neurological progression once symptoms have appeared. However, in pre-symptomatic males with X-ALD (identified through newborn screening or family testing before brain MRI changes appear), Lorenzo's Oil combined with a low-VLCFA diet reduces the risk of developing cerebral ALD. It remains an important component of management for asymptomatic boys and men with X-ALD.
The dietary component of Lorenzo's Oil therapy restricts foods high in saturated very-long-chain fatty acids. VLCFAs are found predominantly in:
The diet is NOT a low-fat diet overall — Lorenzo's Oil itself provides significant calories from oleic and erucic acid. It is a VLCFA-restricted, oleic-acid-enriched diet. A registered dietitian experienced in peroxisomal disorders must guide this — the balance of fatty acid types must be carefully calculated.
For adult men with AMN who may or may not be on Lorenzo's Oil but who want to manage weight:
Illness, surgery, dental procedures, or significant physical stress can trigger adrenal crisis if cortisol dose is not increased. Every ALD/AMN patient with adrenal insufficiency must know the sick day rules:
Exercise is beneficial but requires careful planning around cortisol replacement:
| Exercise Type | Suitable? | Notes |
|---|---|---|
| Swimming / hydrotherapy | Excellent | Buoyancy assists with spastic weakness; low fall risk; good for cardiovascular fitness |
| Stationary cycling | Good | No balance demand; adjustable resistance; safe for spastic paraparesis |
| Walking (flat, with aids if needed) | Good where possible | Use walking aids as needed; avoid uneven surfaces with balance impairment |
| Light resistance training | Good with guidance | Preserves upper body strength; avoid heavy lifts that raise cortisol demand sharply |
| Vigorous HIIT / intense intervals | Caution | Very intense exercise increases cortisol demand — pre-dose with 5 mg hydrocortisone before extended vigorous sessions; discuss with endocrinologist |
| Running, contact sports | Usually limited | Spastic paraparesis makes these impractical in most AMN cases |
Pre-exercise cortisol dosing: For exercise sessions longer than 45-60 minutes at moderate-to-vigorous intensity, taking an additional 5 mg hydrocortisone 30-60 minutes before exercise reduces the risk of fatigue, hypoglycaemia, and cortisol deficiency during the session. This is especially important for hot-weather exercise (outdoor exercise in a South African summer).
For boys with childhood cerebral ALD (CCALD) with early MRI changes, HSCT can halt cerebral demyelination. Post-transplant nutrition is managed by the transplant team. Weight gain from post-transplant immunosuppression (corticosteroids, cyclosporine) is common and should be addressed gradually once the transplant is stable — discuss timing with the treating team.
Gene therapy (Skysona / elivaldogene autotemcel) received European approval for early CCALD and represents a significant advance. Nutritional support post-gene-therapy follows the transplant-like protocols of the treating centre.
ALD/AMN is managed by a combination of metabolic physicians, neurologists, and endocrinologists. The main centres are at Wits Donald Gordon Medical Centre (Johannesburg), Red Cross War Memorial Children's Hospital (Cape Town), and Steve Biko Academic Hospital (Pretoria). The ALD/AMN Alliance (international) provides patient support resources accessible to South African families.
More rare condition guides: Browse our full library of South African weight management articles for conditions including Addison's Disease, adrenal tumours, and other endocrine disorders.