u/tx8708

Hi r/Cholesterol,

Most posts here are about getting LDL and apoB down. I'm posting about the opposite problem — a rare genetic disorder where they're already so low that the diagnosis gets missed entirely.

Familial Hypobetalipoproteinemia (FHBL) is essentially the mirror image of Familial Hypercholesterolemia (FH). Same general family of genes (APOB is the most common cause), same idea (single-gene defect affecting lipoprotein metabolism), opposite phenotype. Where FH causes lifelong dangerously high LDL and accelerated atherosclerosis, FHBL causes lifelong (potentially) dangerously LOW LDL — and a different but very real disease burden.

The numbers

I'll use myself as a reference point:

• Total cholesterol: 75-94 mg/dL across 5 years documented
• LDL: 17-35 mg/dL across 5 years (every value below the 1st population percentile)
• HDL: 40-48 mg/dL (normal — HDL doesn't carry apoB, so it's spared)
• ApoB: 20 mg/dL (measured November 2021)
• Triglycerides: 55-112 mg/dL

For this community, apoB at 20 means something: that's well below the 5th percentile (~50 mg/dL) and into the range the published literature calls "very low." Not "great cardiovascular-protective low." Pathologic low.

Why this isn't just "great numbers"

In FHBL the underlying biology is broken. The body can't properly assemble apoB-containing lipoproteins, which means:

• Fat-soluble vitamins (A, D, E, K) can't be transported normally to tissues
• The liver can't export triglycerides as VLDL, so fat accumulates → NAFLD → NASH → potentially fibrosis and cirrhosis
• Decades of vitamin E deficiency can produce a recognized neurologic syndrome (peripheral neuropathy, ataxia, myopathy, retinopathy)
• Two recent 2025 papers (Lou et al., J Clin Transl Hepatol; Sürücü Kara et al., J Clin Lipidol) document 4 to 8 times increased cirrhosis and HCC risk in this population independent of obesity, alcohol, or hepatitis
• Heterozygous patients with markedly low apoB are now recommended to be treated at the same level as homozygous patients

I have NASH, documented vitamin E deficiency, and progressive neurological symptoms going back years. My paternal aunt died at 63 of "non-alcoholic cirrhosis" — likely from undiagnosed FHBL. My father has lifelong unusually low cholesterol that nobody ever investigated. Three generations on what's almost certainly the paternal side, with one death attributable to the disease.

Why I'm posting here specifically

This community pays closer attention to apoB and lipid genetics than almost any other patient community on Reddit — which is exactly the population most likely to spot FHBL when they see it. So:

• If you've ever seen a relative with bizarrely low cholesterol (TC under 100, LDL under 50) and had it brushed off as "they have great numbers," it's worth knowing FHBL exists. A single apoB level is essentially the screening test.
• If you're FH-aware and curious about the inherited-dyslipidemia spectrum, FHBL is the underdiscussed counterpart. Same general gene family, opposite phenotype.
• If you know clinicians or researchers in the lipid space who don't think much about FHBL, the 2025 literature is meaningfully changing the picture. The "asymptomatic heterozygote" framing is being directly challenged.

Quick note on treatment

Treatment is not a statin (obviously — you'd push the LDL even lower and worsen the underlying problem). It's high-dose fat-soluble vitamin supplementation (vitamin E in particular — recommended doses are dramatically higher than anything in a multivitamin: 100-300 IU/kg/day for biallelic-equivalent treatment), low-fat diet to reduce hepatic substrate, longitudinal liver surveillance, and family cascade screening.

A small ask

I'm rebuilding r/fhbl as a community for FHBL patients and their families. If anyone here knows someone with this condition — or fits the profile themselves — please send them our way. The subreddit was quiet for five years; the recent literature gives us a lot more to talk about now.

Thanks for reading. r/cholesterol is one of the few places I'd expect this disease to actually get noticed when it shows up.

— Bill

Hi r/rarediseases ,

I'm posting to raise awareness for a rare disease I think has unusual potential to be caught earlier and treated better, but that almost everyone — including most clinicians — doesn't recognize: Familial Hypobetalipoproteinemia (FHBL).

What it is, in plain language

FHBL is a genetic condition (most often caused by APOB gene mutations) that prevents the body from properly producing and packaging cholesterol-carrying particles. People with it have:

• Lifelong abnormally LOW cholesterol (the opposite of what most lipid disorders cause)
• Very low or undetectable apolipoprotein B
• Often unexplained fatty liver disease
• Often fat-soluble vitamin deficiencies (A, D, E, K)
• Sometimes progressive neurological symptoms from cumulative vitamin E deficiency
• A family history that frequently includes unexplained "non-alcoholic" cirrhosis

Heterozygous FHBL affects roughly 1 in 1,000 to 3,000 people. The biallelic form is much rarer. Many heterozygous patients have meaningful disease that has historically been considered asymptomatic by guidelines.

Why it gets missed

This is the part I most want to surface in this community. When a doctor sees extremely low cholesterol in a patient, the default reaction is: "great, no cardiovascular risk, move on." They write a normal note and the patient never learns this is a finding worth investigating.

But FHBL patients have a different risk profile — protected from atherosclerotic heart disease, but vulnerable to:

• Cumulative liver damage (steatosis → NASH → fibrosis → cirrhosis → liver cancer)
• Vitamin E deficiency neuropathy and myopathy that can be misdiagnosed as fibromyalgia or functional disorders
• Family clusters where multiple relatives have unexplained "non-alcoholic" cirrhosis or mystery liver issues

The 2025 published literature now documents 4 to 8 times the general population risk for cirrhosis and primary liver cancer in patients with this profile, independent of obesity, alcohol, or hepatitis. Most primary care providers haven't caught up to that yet.

My story, briefly

I'm 38. I had unexplained NAFLD diagnosed at age 23 while active-duty military, with normal BMI, exercising daily, no alcohol use. Nobody could figure out why. My paternal aunt died at 63 of "non-alcoholic cirrhosis" — also no clinical explanation found. My father has lifelong unusually low cholesterol that has never been investigated.

A nurse caught my low cholesterol incidentally during a strep visit in 2017 and said "you should look into this." I went home, researched, found FHBL, and got diagnosed in 2020. I started r/fhbl that same year because there was nowhere for FHBL patients to find each other. For most of the past five years, I was the only member of my own subreddit.

I'm finally posting publicly because new literature plus my own renewed work give us much more to share.

What I'm asking

• If you have FHBL or suspect you might, please come find us at r/fhbl. We're rebuilding the community.
• If someone in your family has unexplained low cholesterol that nobody's investigated, consider whether FHBL might be hiding there. The diagnostic biomarker (apolipoprotein B) is a single inexpensive blood test.
• If you have unexplained NAFLD, fat-soluble vitamin deficiencies, or progressive neurologic symptomsalongside low LDL, pursue genetic testing. This community already knows that aggressive self-advocacy is often the only path to diagnosis.
• If you know someone in healthcare or research with an interest in inherited dyslipidemia, please share this. FHBL needs more clinical visibility.

Thanks for reading. Solidarity to everyone in this community navigating your own rare disease journey. The work you all do to find each other and support each other is genuinely meaningful.

— Bill (r/fhbl founder)