What Are The Symptoms Of Velocardiofacial Syndrome?

Velocardiofacial syndrome is a condition characterized by numerous problems in the body that may include feeding issues, speech issues, low calcium levels, behavioral issues, facial deformities, learning problems, impaired immunity, and renal problems. Velocardiofacial syndrome occurs when there is a spontaneous or inherited genetic abnormality in chromosome 22, where the q11.2 section of the chromosome is absent.

Only a handful of specific genes have been identified out of all of the missing genes that can explain some of the features of velocardiofacial syndrome patients. Diagnosis of velocardiofacial syndrome is made based on findings in physical examination, medical history, and fluorescence in situ hybridization blood test. Once the gene deletion has been detected, the different features of the condition can be treated individually.

Cleft Palate

Individuals affected by velocardiofacial syndrome may have the characteristic birth defect referred to as a cleft palate. Cleft palate describes a defect where two sections of the individual's skull that develop into the hard palate fail to fuse completely. A gap or cleft is also seen in a patient's soft palate. A gap in the jaw may be present in individuals who have a complete cleft palate. A cleft palate may appear to look like a hole in the roof of the mouth of an individual affected by an incomplete cleft palate.

Velocardiofacial syndrome patients have a deletion in the TBX1 gene. The mechanism and phenotype in this gene that causes the cleft palate are not fully understood, but it is thought to involve an increased tongue height, a perturbed proliferation of certain cells, abnormal elevation of the palatal shelf, and or reduced palatal shelf width. Corrective surgery for the cleft palate can help prevent dental problems, low self-confidence, ear infections, feeding problems, and speech issues.

Issues Fighting Infections

Velocardiofacial syndrome is known to produce issues with fighting infections in patients. An individual's immune system is formed with the development of their thymus gland, which starts early in their fetal development. The number of fully matured infection-fighting T-lymphocyte cells produced in an individual's body is directly correlated with the size of their thymus gland. Velocardiofacial syndrome patients may have an absent or underdeveloped thymus gland. The underdevelopment or absence of the thymus gland poses a threat to patients because their bodies do not have the tools it needs to fight foreign pathogens effectively.

As a result, an individual affected by velocardiofacial syndrome will experience more frequent illness and infections than their peers. In addition, these patients are more likely to develop an autoimmune disorder at some point in their lives because their immune system is regularly exposed to numerous infection-causing agents, making them more vulnerable to immune dysfunction.

Distinctive Facial Features

Velocardiofacial syndrome patients tend to exhibit distinctive facial features healthy individuals would not usually have. Abnormalities or deletion of the TBX1 gene can cause craniofacial dysmorphism, but the mechanism behind this process is not clear. Craniofacial dysmorphism is a group of anomalies or malformations of the craniofacial region. The patient's face may exhibit a nasal tip that can be described as bulbous, parietal bones that are more prominent than normal, and a round shape during their infancy.

In the individual's older years, their face tends to appear hypotonic and long, features narrow palpebral fissures, a squared nasal, thin alae nasi and narrow alar base, and puffy upper eyelids. A patient may have low set ears, a down-slanted mouth, cheeks that appear flat, blue discoloration underneath the eyes, cleft lip or palate, an underdeveloped lower jaw, and a thin upper lip.

Heart Defects

Approximately seventy-five percent of individuals affected by velocardiofacial syndrome will have abnormalities in their cardiac system (heart defect). The problems with the cardiac system are typically conotruncal, which means the problems are secondary to the abnormal development of the outflow mechanism of the individual's developing heart. A patient may have what is referred to as interrupted aortic arch type B, where the aortic arch is absent or discontinued between the left subclavian artery and left carotid artery.

They may have truncus arteriosus, where only one vessel exits the left and right ventricles instead of the typical two vessels. Another common cardiac defect is called tetralogy of Fallot, where the patient has a misplaced aorta, a right ventricular wall that is too thick, ventricular septal defect, and pulmonary valve stiffness or stenosis. Individuals who have any type of anomaly of their aortic arch are more likely to have velocardiofacial syndrome.

Issues With Kidneys

One of the main features of velocardiofacial syndrome is issues with the kidneys, which can be the result of any of many congenital anomalies that may occur in their kidney and urinary tract. In rare cases, a patient may be born without a second kidney due to the gene deletion in velocardiofacial syndrome. If one of the kidneys is not entirely missing, patients may have one kidney that is underdeveloped and not functioning properly.

The lack of proper development in these organs is often referred to as kidney dysplasia. Velocardiofacial syndrome patients may develop cystic kidneys, which are kidneys with multiple fluid-filled pockets or cysts in them that interfere with their function. The cysts can grow in size and damage the delicate structures in the kidney responsible for filtering the blood.