Signs, Symptoms, and the Road to Diagnosis

Familial Partial Lipodystrophy (FPLD) is not a condition of weight, but of weight distribution. Because your body cannot store fat in the normal “warehouses” under the skin of your arms and legs, it is forced to store that energy elsewhere ^[1][2].

(Note: The following physical signs primarily apply to patients with loss-of-function AKT2 variants that cause lipodystrophy. Those with activating variants causing hypoglycemia may not experience these changes.)

The physical hallmarks of FPLD often become visible around puberty and include:

• Lipoatrophy (Fat Loss): A selective loss of fat from the legs, hips, and arms. This can make your limbs appear very thin or intensely muscular, as there is no layer of fat to soften the appearance of the muscles ^[1][3].
• Prominent Veins: Because the subcutaneous fat is missing, veins in the arms and legs may appear unusually visible or “bulging” (phlebomegaly) ^[4][3].
• Adipose Accumulation: Fat that cannot go to the limbs may accumulate in the face, neck, and upper back (sometimes called a “buffalo hump”), or deep inside the abdomen around the organs (visceral fat) ^[2][1].
• Acanthosis Nigricans: Dark, velvety patches of skin, typically in the armpits or around the neck, which are a physical sign of severe insulin resistance ^[5][6].

How Doctors Diagnose FPLD

A diagnosis usually begins with a clinical suspicion framework. In many expert guidelines, a clinician might suspect FPLD if there is lower-limb lipoatrophy (noticeable fat loss in the legs) plus at least one of the following metabolic clues ^[7]:

1. Severe Hypertriglyceridemia: Very high levels of fat (triglycerides) in the blood ^[7][8].
2. Early-Onset Diabetes: High blood sugar that often requires unusually high doses of insulin to manage ^[2][9].
3. Metabolic Liver Disease: Fat accumulation in the liver (steatosis) ^[7][6].
4. Reproductive Signs: In women, this often presents as Polycystic Ovary Syndrome (PCOS) features, such as irregular periods or excess hair growth (hirsutism) ^[7][10].

Tools Used to Support the Diagnosis

While a physical exam is the most important tool, your care team may use objective tests to map your body fat. It is important to note that there is no single numerical cutoff that confirms disease; these are interpreted by your clinician as part of a larger picture:

• Skinfold Measurements: A technician uses calipers to measure the thickness of fat at specific points. Very low thigh or calf skinfolds can support a diagnosis of FPLD, though measurements vary by age, sex, and technician ^[11][12].
• DXA Scan: Similar to a bone density scan, a DXA can calculate your trunk-to-leg fat ratio. In FPLD, this ratio is typically much higher than normal because the legs are depleted of fat while the trunk is not ^[13][14].
• Whole-Body MRI: This provides a detailed map of exactly where fat is stored (and where it is missing), helping to distinguish FPLD from other conditions ^[14][15].
• Genetic Testing: Finding a pathogenic variant in the AKT2 gene supports the diagnosis and helps predict your specific metabolic risks ^[5][2]. However, this must always be matched with your physical symptoms.

Why Misdiagnosis is Common

Because FPLD is so rare, it is frequently mistaken for more common conditions. You may have been treated for years for one of the following before receiving your AKT2 diagnosis:

• Type 2 Diabetes: Doctors may assume a patient has “standard” Type 2 diabetes, but they may be puzzled by how thin the patient’s legs are or how much insulin they require ^[6][9].
• Polycystic Ovary Syndrome (PCOS): The severe insulin resistance in FPLD often causes the same hormonal imbalances as PCOS. If a patient has PCOS symptoms plus very high triglycerides or thin limbs, FPLD should be considered ^[10][16].
• Cushing Syndrome: Because both conditions can cause fat accumulation in the face and neck while the limbs remain thin, they can look remarkably similar. However, the cause of the fat distribution is entirely different ^[1][4].
• Anorexia Nervosa: In some cases, the extreme lack of visible fat on the limbs can lead to a misdiagnosis of an eating disorder, even though the patient is eating normally ^[17][6].

Understanding that your symptoms are caused by a genetic “wiring” issue in the AKT2 gene—rather than lifestyle or a common hormonal disorder—is the first step toward a more targeted and effective treatment plan.