Fanconi anemia (FA) is a rare genetic disorder that affects young children, but they usually have no symptoms early in life.
The clinical manifestations of FA develop over time and involve many organ systems. Clinical suspicion of FA is primarily based on physical defects at birth (eg, heart defects or deformed hands or arms), and growth delays.
Later in life between the ages of 5 and 10, children with FA often experience life-threatening bone marrow failure, which can lead to symptoms including fatigue, easy bruising, frequent infections, and bleeding from the gums or nose.
Because symptoms are highly variable and many FA symptoms overlap those observed in other syndromes, it is nearly impossible to make a reliable diagnosis based on clinical features. The most common way to diagnose FA is to draw blood and test it for chromosomal breaks.
Chromosomal breakage tests and other tests that can be used to diagnose FA will be discussed here.
Evaluation of Fanconi anemia usually begins with a review of the patient’s medical and family history, inquiries about current symptoms, and a complete physical examination. Children are primarily affected by FA, so parents usually answer questions during the assessment.
A medical history that takes your family history and signs and symptoms into account, as well as a focused physical exam to look for dark spots known as café-au-lait spots, are essential for an accurate diagnosis of FA.
Keen observation of common physical examination findings aplastic anemia It may also raise clinical suspicion of FA by healthcare providers. These findings include:
- short and small
- Difficulty breathing (shortness of breath)
- petechiae (small purple-brown spots due to subcutaneous hemorrhage)
- ecchymosis (discoloration all over the body due to bruising, or bleeding under the skin)
- jaundice (yellowing of skin and whites of eyes)
- pale (morbidly pale)
During the physical exam, the healthcare provider will take family and medical history and look for signs of FA, including café-au-lait spots, growth retardation, and symptoms of anemia such as fatigue, shortness of breath, and easy bruising.
Labs and Testing
The most common test for FA is a blood test called a chromosome break (CB) test.it tests Genome Instability (increased tendency to mutate DNA during cell division) – a hallmark feature of FA.
During CB testing, blood was exposed to one of three DNA cross-linkers to which FA patients were allergic. If there is evidence of chromosomal breakage after exposure, FA can be diagnosed.
Prenatal diagnosis can be done by CB testing on fetal blood, or by genetic testing if the mutation is known. The CB test can also be done on a blood sample from the baby after birth.
Everyone with a diagnosis of FA should be referred to hematologist (Physicians specializing in blood disorders) with expertise in medical monitoring and management in FA.
FA Complementary Type
After an FA diagnosis is made, your hematologist may wish to determine your FA supplementation group to help guide medical management and inform future treatment decisions
Complementary group testing is used to classify patients with FA according to the specific genetic defect that causes FA. Additional blood tests can identify specific changes in your DNA.
Since FA usually involves some bone marrow dysfunction, a complete blood count (CBC) is also required. The most common blood and bone marrow-related problems include:
- Anemia: Low red blood cell counts, which can lead to weakness and fatigue
- Thrombocytopenia: Low platelet count, causing spontaneous bleeding in the skin and mucous membranes
- neutropenia: Low levels of neutrophils (type of white blood cells), which can lead to an increased risk of serious infections
- leukemia and myelodysplastic syndrome (MDS): Cancer or precancerous lesions of hematopoietic cells in the bone marrow
If one or more blood cell types are low, a bone marrow biopsy (using a hollow needle to remove a sample of bone marrow and send it to a lab for testing) may be recommended.
An electrocardiogram (ECG) can be used to detect abnormal heart rhythms that can indicate heart defects.
To determine the extent of disease in an individual diagnosed with FA, the following evaluations are recommended as needed:
- Ultrasound of the kidneys and urinary tract
- Formal hearing test (audiology exam)
- developmental assessment
- Referral to necessary specialists as needed
Other recommended exams include:
- ophthalmology Exam to assess vision
- ENT Head and neck cancer screening starting around age 10
- gynecology age-appropriate exam
The 20 Most Common Physician Specialties
The most common test for FA is a blood test called a chromosome breakage test. Once a diagnosis of FA is made, additional tests, including CBC tests, electrocardiograms, and specialist examinations, can be performed to determine the extent and progression of the disease.
Patients with Fanconi anemia have a higher incidence of central nervous system (CNS) abnormalities, especially in posterior fossa (small space in the skull), corpus callosum (bundles of nerve fibers that connect the hemispheres of the brain), and pituitary glands (small endocrine glands at the base of the brain that regulate many bodily functions) – than those without the disease. To evaluate these abnormalities, your healthcare provider may order magnetic resonance imaging (MRI) of the brain.
FA can affect almost any organ in the body and is often associated with congenital (birth) abnormalities. Therefore, computed tomography (CT) scans or MRI imaging of the entire body can also be performed. These images may show physical or organ defects, including:
- Thumb and arm abnormalities, such as extra, misshapen, or missing thumbs and fingers or underdeveloped or missing thumbs radius (one of the forearm bones)
- Bone abnormalities in the hip, spine, or ribs
- Structural kidney defects, such as horseshoe kidney or kidney deficiency
- male reproductive organs
- Tissue defects in isolated hearts
Ultrasound can also be used to look for abnormalities of the urinary tract in both men and women. Pelvic ultrasound can be used to evaluate female genital tract malformations.
Imaging tests are mainly used to determine the extent of the disease after diagnosis. Imaging tests may include brain MRI, CT scan, whole-body MRI, and ultrasound.
The way FA manifests in individuals varies widely, making accurate diagnosis based on symptoms alone difficult. Therefore, the diagnosis of FA is often delayed until the patient presents with bone marrow failure (BMF) or malignancy.
FA should be considered in the differential diagnosis of all young patients with bone marrow failure (BMF) of unknown etiology. Other cancer susceptibility syndromes—such as Bloom syndrome, Rothmund-Thomson syndrome, or Werner syndrome—or other syndromes that increase the risk of congenital or acquired BMF must also be excluded.
Other conditions that may cause anemia, congenital malformations, and/or symptoms of BMF include:
- malformation syndrome (Dubowitz, Sekel, Holt Oram, Baller-Jeroldand Nijmegen fracture syndrome, dyskeratosis congenitaVACTERL Association, Blackfan-Diamond Anemia)
- congenital dyserythropoietic anemia (CDA)
- myelodysplasia syndrome
- cystic fibrosis
Fanconi anemia is primarily diagnosed by a specialized blood test called a chromosome breakage test. This test can be done with fetal blood before birth or after birth if FA is suspected.
After FA is confirmed, your healthcare provider will refer you and your child to a hematologist (a doctor who specializes in blood disorders). You or your child will also undergo additional tests, including blood tests, physical examinations, and imaging tests to determine the extent of the disease. This will help your healthcare team decide how best to manage future conditions.
Obtaining an early and accurate diagnosis of Fanconi anemia (FA) is often difficult because FA is highly variable both genetically and in each individual.
In other words, young children with FA have multiple disorders, and one case may look completely different from the next. Therefore, in many cases, diagnosis may be delayed until bone marrow failure or cancer (leukemia) develops. Therefore, it is not uncommon for delayed or misdiagnosed diagnoses, and incorrect treatment to be scheduled.
If FA is performed in your family, or you suspect that your child may have the disorder, do not delay in finding a trusted healthcare provider and advocating for chromosome breakage testing to confirm the diagnosis. This will help your family get on the right path to monitor and manage the disease and find the support you need.