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:

References

1. Rezk T, Gilbertson JA, Rowczenio D, Bass P, Lachmann HJ, Wechalekar 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/

3. Picken MM. Alect2 amyloidosis: primum non nocere (first, do no harm). Kidney Int. 2014 Aug;86(2):229–32.

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8. Said SM, Sethi S, Valeri AM, Chang A, Nast CC, Krahl L, et al. Characterization and outcomes of renal leukocyte chemotactic factor 2-associated amyloidosis. Kidney Int. 2014 Aug;86(2):370–7.

9. Jiménez-Zepeda VH, Leung N. ALECT2 amyloidosis: a new type of systemic amyloid highly prevalent in the Hispanic population. Rev Investig Clin Organo Hosp Enfermedades Nutr. 2014 Jun;66(3):269–73.