As pregnancy progresses, the baby increases in size and the amount of fetal DNA shed into the maternal blood stream increases. At 10 weeks, the amount of fetal DNA should suffice to successfully complete the test. However, there may be rare instances where the amount of fetal DNA in the sample sent in is too low.

The test can be performed on women who conceived via assisted reproductive technology (ART) such as In-vitro fertilization, including use of a donor egg.

The test does provide very accurate results but is not 100% conclusive. The results will provide a very good indication to your doctor as to whether trisomies 21, 18, 13 or sex chromosome abnormalities are present. The test has been shown to be the most accurate and sensitive test available.

The non-invasive prenatal test for aneuploidies is extremely accurate and it will greatly reduce the need for any further testing. That said, depending on the results of your test, your gynecologist may suggest further invasive tests like amniocentesis.a

5pCri-du-chat (cat’s cry) syndrome, also known as 5p- (5p minus) syndrome, is a chromosomal condition that results when a piece of chromosome 5 is missing. Infants with this condition often have a high-pitched cry that sounds like that of a cat. The disorder is characterized by intellectual disability and delayed development, small head size (microcephaly), low birth weight, and weak muscle tone (hypotonia) in infancy. About 10 percent of people with cri-du-chat syndrome inherit the chromosome abnormality from an unaffected parent. In these cases, the parent carries a chromosomal rearrangement called a balanced translocation, in which no genetic material is gained or lost.

1p36

1p36 deletion syndrome is a disorder that typically causes severe intellectual disability. Most affected individuals do not speak, or speak only a few words. Affected individuals usually have weak muscle tone (hypotonia) and swallowing difficulties (dysphagia). Some have abnormalities of the skeleton, heart, gastrointestinal system, kidneys, or genitalia. About 20 percent of people with 1p36 deletion syndrome inherit the chromosome with a deleted segment from an unaffected parent. In these cases, the parent carries a chromosomal rearrangement called a balanced translocation, in which no genetic material is gained or lost.

2q33.1

Features include developmental delay; significant speech delay with no speech in most cases; a degree of learning difficulty or disability (usually severe); slow growth before and after birth; severe, persisting feeding difficulties, often requiring nasogastric tube feeding, and failure to thrive; High or cleft palate or bifid uvula; Crowded teeth with abnormally shaped teeth and some missing teeth; Behaviour patterns include hyperactivity, chaotic behaviour and a happy personality with bouts of anxiety or aggression.

16p12.2

Findings commonly observed in children with this deletion include: developmental delay, cognitive impairment (ranges from mild to profound), growth impairment (including short stature), cardiac malformations, epilepsy, and psychiatric and/or behavioural problems. Other findings can include: hearing loss, dental abnormalities, renal and genital anomalies (the latter in males), and cleft palate ± cleft lip.

DGS2 I associated with the proximal deletion of chromosome 10p14-p13, which is associated with cardiac and craniofacial abnormalities. Patients may show cardiac defects, immune deficiency, cleft palate, facial dysmorphia, developmental delay, microcephaly, microphthalmia and hypotelorism.

Jacobsen syndrome is a condition caused by a loss of genetic material from chromosome 11.

The signs and symptoms of Jacobsen syndrome vary considerably. Most affected individuals have delayed development, including the development of motor skills (such as sitting, standing, and walking) and speech. Most also have cognitive impairment and learning difficulties. Behavioural problems have been reported, including compulsive behaviour (such as shredding paper), a short attention span, and easy distractibility. Many people with Jacobsen syndrome have been diagnosed with attention deficit-hyperactivity disorder (ADHD). Jacobsen syndrome is also characterized by distinctive facial features. These include small and low-set ears, widely set eyes (hypertelorism) with droopy eyelids (ptosis), skin folds covering the inner corner of the eyes (epicanthal folds), a broad nasal bridge, downturned corners of the mouth, a thin upper lip, and a small lower jaw. Affected individuals often have a large head size (macrocephaly) and a skull abnormality called trigonocephaly, which gives the forehead a pointed appearance. More than 90 percent of people with Jacobsen syndrome have a bleeding disorder called Paris-Trousseau syndrome due to a platelet disorder. This condition causes a lifelong risk of abnormal bleeding and easy bruising. Other features of Jacobsen syndrome can include heart defects, feeding difficulties in infancy, short stature, frequent ear and sinus infections, and skeletal abnormalities. The disorder can also affect the digestive system, kidneys, and genitalia. The life expectancy of people with Jacobsen syndrome is unknown, although affected individuals have lived into adulthood.

Van der Woude syndrome is a condition that affects the development of the face with cleft lip, a cleft palate or both. Affected individuals usually have pits near the centre of the lower lip, which may appear moist due to the presence of salivary and mucous glands in the pits.

People with van der Woude syndrome who have cleft lip and/or palate, like other individuals with these facial conditions, have an increased risk of delayed language development, learning disabilities, or other mild cognitive problems. The majority of VWS cases are caused by haploinsufficiency due to mutations in the interferon regulatory factor 6 gene (IRF6) on chromosome 1 in the 1p32-p41 region known as VWS locus 1.

Prader-Willi syndrome is a complex genetic condition that affects many parts of the body. In infancy, this condition is characterized by weak muscle tone (hypotonia), feeding difficulties, poor growth, and delayed development. Beginning in childhood, affected individuals develop an insatiable appetite, which leads to chronic overeating (hyperphagia) and obesity. Some people with Prader-Willi syndrome, particularly those with obesity, also develop type 2 diabetes mellitus. Most cases of Prader-Willi syndrome (about 70 percent) occur when a segment of the paternal chromosome 15 is deleted in each cell. People with this chromosomal change are missing certain critical genes in this region because the genes on the paternal copy have been deleted, and the genes on the maternal copy are inactive. In another 25 percent of cases, a person with Prader-Willi syndrome has two maternal copies of chromosome 15 instead of one copy from each parent. This phenomenon is called maternal uniparental disomy. Rarely, Prader-Willi syndrome can also be caused by a chromosomal rearrangement called a translocation, or by a mutation or other defect that abnormally inactivates genes on the paternal chromosome 15.

Angelman syndrome is a complex genetic disorder that primarily affects the nervous system. Characteristic features of this condition include delayed development, intellectual disability, severe speech impairment, and problems with movement and ataxia. Most affected children also have recurrent epilepsy and a small head size (microcephaly). Delayed development becomes noticeable by the age of 6 to 12 months, and other common signs and symptoms usually appear in early childhood. Many of the characteristic features of Angelman syndrome result from the loss of function of a gene called UBE3A. Several different genetic mechanisms can inactivate or delete the maternal copy of the UBE3A gene. Most cases of Angelman syndrome (about 70 percent) occur when a segment of the maternal chromosome 15 containing this gene is deleted. In other cases (about 11 percent), Angelman syndrome is caused by a mutation in the maternal copy of the UBE3A gene. In a small percentage of cases, Angelman syndrome results when a person inherits two paternal copies of chromosome 15 instead of one copy from each parent. This phenomenon is called paternal uniparental disomy. Rarely, Angelman syndrome can also be caused by a chromosomal rearrangement called a translocation, or by a mutation or other defect in the region of DNA that controls activation of the UBE3A gene. These genetic changes can abnormally inactivate UBE3A or other genes on the maternal copy of chromosome 15.