Discussion:
Amyloid is a term was first adopted in 1854 by Rudolph Virchow, first
described by a German botanist Mattias Schleiden in 1838 as a plant
starch, to refer to starch like bodies in the nervous system when
exposed to iodine (5,6).
Amyloidosis is a spectrum of disorders that share the pathology of
misfolded protein accumulation in various organs in the body originating
from diverse etiology. 30 types of protein were identified to cause
amyloid formation which causes a toxic effect in the tissues (3).
The most common type of these proteins in the developed countries is
derived from the immunoglobulin light chain namely AL, there is also the
amyloid protein that is derived from amyloid A namely AA, and amyloid
derived from transthyretin.
Another type, known to cause accumulation in patients with chronic
kidney disease, is derived from B2 microglobulin. A minor percentage of
amyloidosis cases are hereditary.
Large case series showed that the most common type of amyloidosis is AL
and AA in the US, but in the last few years, more case series emphasized
that Lect2 amyloidosis is more common in the Hispanic population.
Studies outside the US showed a common prevalence of Lect2 amyloidosis
in middle eastern, Egyptian, Sudanese, Pakistani-Kashmiri and
Punjabi-Indian, populations (2,3,7), our patient was Punjabi descent.
Lect2 is a chemotactic factor for neutrophils and it has a role in
chondrocytes and osteoblasts stimulation. It is mainly produced by the
liver and it is overexpressed in hepatocellular carcinoma and other
liver diseases, it was suggested that Lect2 is an acute phase reactant
produced as a response to hepatic inflammation and it plays a role in
hepatic regeneration (1,3).
Lect2 amyloidosis is not hereditary although some familial cases were
described, the gene of this protein is located on chromosome 5
(5q31.1-q32) but abnormality on chromosome 7 was also reported. All
cases in one case series by Rezk et al. except for one were found to be
homozygous for the G allele and the other case was heterozygous (1,7).
Said et al., reported a case series of 72 patients with renal Alect2
were mostly from the Hispanic population showed that nephrotic syndrome
and haematuria were rare, up to one-third of the patients developed
end-stage renal disease in the duration of 26 months due to glomerular
involvement (8).
Rezk et al. studied 24 patients with Lect2 amyloidosis and found that
hepatic involvement was not associated with significant liver function
derangement and none with cardiac involvement. This may be the reason
behind its benign course in most cases (1).
The diagnosis is usually made by kidney or liver biopsy.
There is no specific treatment for Lect2 amyloidosis, most of the time,
the treatment is supportive mainly directed for kidney disease (9).
The importance of identifying this disease is to avoid toxic
chemotherapy when it is diagnosed as AL amyloidosis. More studies are
needed to identify this subtype of amyloidosis and the possibility of
severe hepatic disease presentation.
Author Contributions:
- Hussam Almasri: corresponding author, manuscript writing
- Abdo Lutf: clinical follow up
- Almurtada Razok: manuscript writing
- Ahmed Badi: clinical supervision
- Muneera Almohannadi: clinical supervision
- Mahir Petkar: pathology input
- Abdelnaser Elzouki: manuscript review
References
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AD, et al. Diagnosis, pathogenesis and outcome in leucocyte chemotactic
factor 2 (ALECT2) amyloidosis. Nephrol Dial Transplant. 2018 Feb
1;33(2):241–7.
2. Leukocyte cell-derived chemotaxin 2 (LECT2)-associated amyloidosis is
a frequent cause of hepatic amyloidosis in the United States - PubMed
[Internet]. [cited 2021 Sep 12]. Available from:
https://pubmed.ncbi.nlm.nih.gov/24415538/
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