Zika is a generally mild illness caused by a virus primarily transmitted through the bite of infected Aedes mosquitoes. The U.S. has 318 reported travel-associated cases; all were travel-associated/imported and included 11 reports of sexual transmission, 157 pregnant women and 1 Guillain Barre syndrome. Approximately one in five people infected with the virus develop the disease, and most people who are infected do not develop symptoms. The most common symptoms of Zika virus are fever, rash, joint pain, and conjunctivitis (red eyes). Symptoms typically begin two to seven days after being bitten by an infected mosquito. In some cases, Zika virus may be transmitted sexually in semen. It can also be transmitted from a pregnant mother to her baby during pregnancy or around the time of birth. Fetuses and infants of pregnant women infected with Zika virus are at increased risk for microcephaly, intracranial calcifications, central nervous system abnormalities and other severe brain defects. The CDC recently estimated that women infected during pregnancy may have a 13% chance of giving birth to a child with microcephaly.
In the recent publication in the NEJM Zika, Virus and Birth Defects — Reviewing the Evidence for Causality, Rasmussen et al. demonstrate that there is “sufficient evidence has accumulated to infer a causal relationship between prenatal Zika virus infection and microcephaly and other severe brain anomalies”. According to the SMFM’s current guidelines, all women who are at risk of infection due to a travel history to an endemic area (http://www.cdc.gov/zika) or exposure through unprotected sex with an infected individual should be offered serum serological screening for Zika virus regardless of whether they are presenting with symptoms. Patients whose serological testing is IgM positive or inconclusive may be offered amniocentesis in combination with serial ultrasounds to assist in identifying microcephaly and microcalcifications. A positive Zika virus RT-PCR result from amniotic fluid would be suggestive of intrauterine infection. This information would be useful for pregnant women and their health care providers to assist in determining clinical management (e.g., antepartum testing, scheduling serial ultrasounds, delivery planning). A negative Zika virus RT-PCR result from amniotic fluid may prompt a work-up for other causes of microcephaly (e.g., other infections, genetic disorders).
CytoGenX is actively coordinating with local health departments and the CDC for Zika testing in pregnant women. Recently the CDC issued guidelines for the prevention of Zika virus infection in pregnant women.
Canavan disease is caused by a defective aspa gene. This gene is located on the p arm of chromosome 17, and is responsible for the production of the enzyme aspartoacylase. This deficiency leads to the buildup of N-acetylaspartic acid (NAA) in the brain. The accumulated NAA causes a chemical imbalance resulting in myelin destruction. Canavan disease is an autosomal recessive disorder.
- Affects approximately 1in 6,400 people of Jewish ancestry
- It is estimated that 1 in 40 Ashkenazi Jewish individuals are carriers
- Mental retardation, loss of previously acquired motor skills, feeding difficulties, abnormal muscle tone (specifically floppiness or stiffness), poor head control, and megalocephaly
- Paralysis, blindness, or seizures may occur
- Symptoms appear in early infancy and progress rapidly
- Children with Canavan disease cannot crawl, walk, sit or talk
- Most children with Canavan disease will not live past the age of ten
There is currently no cure or effective treatment for Canavan disease
DiGeorge syndrome is caused by a deletion on chromosome 22. Approximately 90% of patients with DiGeorge syndrome have a deletion at the 22q11.2 region. A small number of cases of DGS have defects on other chromosomes, notably 10p13. DiGeorge syndrome is inherited in an autosomal dominant manner.
- Affects approximately 1 in 3,000 to 1 in 4,000 individuals
- Most of the 22q11.2 deletion cases are de novo, however in about 10% of families, the deletion is inherited and other family members are affected or at risk for passing this deletion to their children
- There is an overall 0.025% risk of the 22q11 deletion syndrome in the general population
- Conotruncal heart defects (Tetralogy of Fallot, interrupted aortic arch, ventricular septal defects, vascular rings)
- Palatal abnormalities
- Feeding difficulties
- Immunodeficiency due to absence or malformation of thymus
- Hypocalcemia due to absence of malformation of parathyroid glands
- Craniofacial abnormalities (see below)
- Hearing loss or abnormal ear exams
- Genitourinary anomalies (absent or malformed kidney)
- Mental retardation (typically borderline to mild)
- IQs are generally in the 70 to 90 range
- Psychiatric disorders in adults (e.g., schizophrenia, bipolar disorder)
- Small ears with squared upper ear
- Hooded eyelids
- Unilateral facial weakness
- Small mouth, chin, and side areas of the nose tip
- Palatal abnormalities (Cleft lip and/or palate for example)
- It is important that the immune problems in infants are identified early so that special precautions may be implemented regarding immunization and blood transfusions
- Most treatment is directed at alleviating symptoms, infections are treated aggressively with antibiotics
- Patients may undergo cardiac surgery for their heart abnormalities
- Hypoparathyroidism causing hypocalcemia is often transient, but may require lifelong vitamin D treatment
- Thymus transplantation can be used to address absence of the thymus in complete DiGeorge syndrome