GENOGRAM OF HEREDITARY HEMORRHAGIC TELANGIECTASIA 2 Genogram of Hereditary Hemorrhagic Telangiectasia

GENOGRAM OF HEREDITARY HEMORRHAGIC TELANGIECTASIA 2
Genogram of Hereditary Hemorrhagic Telangiectasia (HHT)
Etiology and Risk Factors
Hereditary Hemorrhagic Telangiectasia (HHT) is usually caused by the mutation in one
or several genes including GDF2, ENG, SMAD4, and ACVRL1. In some people, however, HHT
is believed to be caused by at least two other unknown genes. More than 80 % of HHT cases are
caused by the mutation of the ENG gene (Rimmer & Lund, 2015). An individual only needs to
inherit one copy of the mutated gene through the autosomal dominant pattern. The disorder is
predominant in both sexes in terms of frequency and severity. Although the disease has been
reported in all races, it is more common with the white patients (McDonald & Pyeritz, 2017).
Additionally, evident research has indicated the distribution of the disease according to
geographic distribution. Prospective parents from a family history of HHT are therefore
recommended to undergo genetic counseling.
Pathogenesis
In HHT patients, blood flows directly from the arteries to the veins without going through
the capillaries first. The condition is what is referred to as arteriovenous malformations (AVMs).
When blood under high-pressure flow directly into the thin and less elastic veins, it usually
results in a strain and compression of the adjacent tissues and occurrence of Hemorrhage is likely
(Huether & McCance, 2017). Near the surface of the skin, the telangiectasia is usually visible as
red markings. The disease is likely to cause numerous complications when the arteriovenous
malformations are located near the brain liver, gastrointestinal tract or in the lungs.
Symptoms
Hereditary Hemorrhagic Telangiectasia is a rare condition whose occurrence is
characterized by multiple telangiectases of mucosa and skin as well as pulmonary arteriovenous
GENOGRAM OF HEREDITARY HEMORRHAGIC TELANGIECTASIA 3
fistulae. The disorder in patients manifests through the multiple Telangiectasias of the mucosa
and skin as well as the visceral organs, cyanosis, exertion dyspnea and recurrent nose bleeding
(epistaxis) (Huether & McCance, 2017). In early childhood, the disorder is characterized by the
focal dilation of the postcapillary venules (Chung, 2015).
The initial stages of this disease are characterized by recurrent nose bleeding and the
occurrence of cutaneous telangiectases in early childhood (Huether & McCance, 2017). In
adults, the disorder can cause right-left shunt as well as hypoxemia. The Telangiectasia can be
observed in the lips, facial skin, and the nasal mucosa. The disorder is usually confirmed by the
pulmonary angiography. The disorder is also diagnosed by the presence of autosomal dominant
inheritance especially when the internal organs are involved in the form of the pulmonary
fistulae (Zagury et al., 2015). Other symptoms of the disease will include anemia, brain abscess,
hematemesis, Melena among others. The disease is treated surgically either via hormonal therapy
or laser which involve the removal of the affected parts of the organ.
Co-morbid Conditions
HHT is mostly reported to occur concurrently with pulmonary hypertension a disorder,
which increases the arteries pressure in the lungs (Law & Davis, 2018). Moreover, pulmonary
embolism is commonly associated with HHT.
Morbidity and Mortality Considerations
According to Rimmer and Lund (2015), estimates 1 in 5000 to 1 in 9000 individuals are
affected by HHT disease in the world’s population. Patients of HHT usually have a reduced life
expectancy compared to the general population. The disease, however, remains undiagnosed in
many patients until eventual catastrophic events such as stroke and sudden death.
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It is worth noting that HHT has no cure and the treatment is therefore supportive and
symptomatic (Tual et al., 2015). The treatment mainly focuses on preventing associated
complications as well as controlling the bleeding.