Hypobetalipoproteinemia: Two Clinical Cases

Background: The familial hypobetalipoproteinemia (FHBL) belongs to a heterogeneous group of monogenic diseases characterized by plasma levels of LDL cholesterol and apolipoprotein B (apoB) < P5. It’s an uncommon disorder with codominant inheritance, being the prevalence of the heterozygous form of 1:1000-1:3000. Heterozygote patients are usually asymptomatic, with hepatic steatosis being the most frequent clinical change with a potential risk of progressing to cirrhosis. It is recommended to perform regular biochemical control and abdominal ultrasound if increased transaminases occur.

Clinical Cases: Female of 12 years (Patient 1) and male of 20 years (P2) treated in the unit of Adolescent Medicine. In control analytics:

P1: Total cholesterol 85 mg/dL, LDL Cholesterol 37 mg/dL, apoB < 26 mg/dL. GOT: 30UI/L, GPT 48 UI/L, GGT 17UI/L.

P2: Total cholesterol 66mg/dL, LDL 13mg/dL, apoB< 26mg/dL, GOT: 25 IU/L, GPT 50UI/L, GGT 38UI/L. Ultrasound: diffuse increase in echogenicity compatible with steatosis.

Pending results of parental lipid screening and genetic study in both patients.

In both cases, secondary causes of hypolipemic were excluded.

Conclusion: LDL low cholesterol forces you to rule out secondary causes of hypolipemia. FHBL is due to mutations in the gene apoB or with less frequency of PCSK9 although in 50% of the cases does not become affiliated with any mutation. Diagnosis is important to prevent the emergence of homozygous FHBL in future generations, which is associated with degenerative neuromuscular diseases and retinal problems.