Alys amyloidosis E85.9

Lysozyme-derived (ALys) amyloidosis, also called familial visceral amyloidosis or Ostertag-type amyloidosis, is a rare, autosomal-dominantly inherited, systemic amyloidosis associated with a wide spectrum of clinical manifestations (Röcken C et al. 2006). It is caused by mutations in the lysozyme gene (LYZ).

Nine amyloidogenic variants and approximately 30 affected families have been described worldwide (Anker S et al. 2022).

Alys can occur as early as early adulthood (Anker S et al. 2022).

The ALys phenotype primarily affects the digestive tract, liver and spleen, kidneys (renal amyloidosis with nephrotic syndrome), lymph nodes, skin (petechial hemorrhages), and lacrimal and salivary glands (the sicca syndrome). Furthermore, cardiac involvement and peripheral neuropathy have been documented. In ALys amyloidosis, proteolytic fragments of lysozyme have been detected in the amyloid deposits.

62-year-old man of Italian origin (Piedmont) diagnosed with ALys associated with the p.Trp82Arg variant of the Lys gene. The patient complained of upper digestive tract symptoms, sicca syndrome, and recent recurrent lung infections. Chest endoscopy revealed a fragile, inflammatory, and granulomatous aspect of the bronchi. Amyloid deposits were noted in the upper digestive tract, salivary glands, temporal artery (cranial arteries are very rarely involved), and tracheobronchial tree. Symptomatic treatment was offered. During follow-up, recurrent pulmonary infections occurred (Kasusitik of Benyamine A et al. 2017). Literature review shows that hereditary ALys with variant p.Trp82Arg is common in patients from Piedmont (Italy).

1. Anker S et al. (2022) Lysozyme amyloidosis-a report on a large German cohort and the characterisation of a novel amyloidogenic lysozyme gene variant. Amyloid 29:245-254.
2. Benyamine A et al. (2017) Hereditary lysozyme amyloidosis with sicca syndrome, digestive, arterial, and tracheobronchial involvement: case-based review. Clin Rheumatol 36: 2623-2628.
3. Röcken C et al. (2006) ALys amyloidosis caused by compound heterozygosity in exon 2 (Thr70Asn) and exon 4 (Trp112Arg) of the lysozyme gene. Hum Mutat 27:119-120