Sporadic pediatric severe familial adenomatous polyposis: A case report

Area of Science:

• Genetics
• Oncology
• Gastroenterology

Background:

• Familial adenomatous polyposis (FAP) is an autosomal dominant hereditary precancerous condition.
• It is caused by germline variants in the adenomatous polyposis coli (APC) gene, leading to gastrointestinal polyps that become cancerous if untreated.
• Genotype-phenotype variability necessitates individual genetic characterization for effective cancer prevention programs.

Purpose of the Study:

• To report a severe, sporadic case of FAP diagnosed in a 2-year-old.
• To highlight the importance of molecular screening in young children presenting with specific symptoms.
• To emphasize the need for early diagnosis and intervention in FAP cases.

Main Methods:

• Case report of a patient with sporadic FAP.
• Genetic analysis to identify pathogenic variants and polymorphisms in the APC gene.
• Clinical evaluation of symptoms including iron-deficiency anemia and rectal bleeding.

Main Results:

• A severe FAP case was diagnosed at age 2 in a patient with a *de novo* pathogenic c.4132 C>T (p.Gln1378X) APC variant.
• The patient was also a carrier of a homozygous c.5465 T>A (p.Asp1822Val) polymorphism, its role in phenotype is undetermined.
• The findings underscore the potential for early-onset FAP.

Conclusions:

• Early molecular screening for FAP should be considered in very young children with iron-deficiency anemia and/or rectal bleeding, irrespective of family history.
• Prompt diagnosis and genetic characterization are vital for implementing personalized cancer prevention and management strategies.
• This case emphasizes the importance of extending diagnostic evaluations to pediatric populations presenting with suggestive symptoms.