DiGeorge syndrome (velocardiofacial syndrome).

DiGeorge syndrome (velocardiofacial syndrome)

Caused by deletion of band q11 region of one copy of chromosome 22.

The deletion follows autosomal dominant inheritance.

It is helpful to test the parents as they may have a milder phenotype and not be aware of it.

However, the majority of cases are de novo.

Patients may have a long face, narrow palpebral fissures and over-folded ear helices. However, the facial phenotype is often subtle.

Affected individuals can have very variable medical complications affecting almost every system:

·       Cardiac defects (particularly tetralogy of Fallot, interrupted aortic arch, ventricular septal defect, and truncus arteriosus)

·       Palatal abnormalities including cleft palate

·       Immune deficiency (impaired T-cell production and function, thymic hypoplasia)

·       Hypocalcemia, especially in neonates (due to parathyroid dysfunction)

·       Renal tract abnormalities

·       Mild to moderate learning difficulties/ developmental delay/ Autism/ADHD.

·     There appears to be an increased incidence of psychiatric disorders, particularly within the schizophrenic spectrum.

Treatments and therapy for 22q11.2 deletion syndrome may include treatments for:

- Assessment of severity of croup using Westley Clinical Scoring System.

 Assessment of severity of croup using Westley Clinical Scoring System

A variety of scoring systems have been developed to evaluate the severity of croup.The most commonly used scoring system has been that of Westley et al.(1).

Assessment of severity of croup using Westley (2) Clinical Scoring System in emergency department, as shown in following table is very useful to plan for staying at observation unit, hospital admission, ICU admission

• Mild croup—Score 0–2; 
•  Moderate croup—Score 3–5;
•  Severe croup—Score 6–11;
•  Impending respiratory failure—Score 12–17. 

 Ibrahim Samaha

References:

1. Cherry, James D. "Croup." New England Journal of Medicine 358.4 (2008): 384-391.
2. Westley CR, Cotton EK, Brooks JG. Nebulized racemic epicontents of this manuscript. nephrine by IPPB for the treatment of croup: a double-blind study. Am J Dis Child 1978 May; 132 (5): 484-7

Microdeletion syndromes

Sub-microscopic deletion of a part of a chromosome (1-3 million bp) that are too small to see on standard microscopy.

Sometimes involves loss of a few contagious genes (contagious gene syndromes).

Sometimes involves micro duplications.

They can be detected using specific FISH testing, MLPA or CGH microarray.

 Examples of microdeletion syndromes:

• DiGeorge syndrome or velocardiofacial syndrome  – most common microdeletion syndrome.
• Prader–Willi syndrome.
• Angelman syndrome.
• Williams syndrome.
• Miller–Dieker syndrome.
• Smith–Magenis syndrome.
• Rubinstein–Taybi syndrome.
• Wolf–Hirschhorn syndrome.
  

- 47, XYY syndrome.

47, XYY syndrome

Also known as Jacobs syndrome

This affects 1 in 1000 live-born boys.

These males are phenotypically normal but tend to be tall.

But affected boys may have hypotonia, hand trembling or involuntary muscle movements, delayed or difficult speech and delayed motor skill development.

Intelligence is usually within normal limits but there is an increased incidence of behavioral abnormalities.

Treatment:

·       speech therapy for speech delay.

·       occupational therapy: for delayed motor skill development.

·       Educational therapy: for learning disabilities.