Aarskog Syndrome
John Smith MA
M Awad MD (Ed.)
Smashwords Edition
****
Copyright 2011 John Smith MA, M Awad MD
Smashwords Edition, License Notes
This ebook is licensed for your personal enjoyment only. This ebook may not be re-sold or given away to other people. If you would like to share this book with another person, please purchase an additional copy for each recipient. If you’re reading this book and did not purchase it, or it was not purchased for your use only, then please return to Smashwords.com and purchase your own copy. Thank you for respecting the hard work of this author.
Contents
Aarskog Syndrome Organizations
Appendix A: Internet Resources / Further Reading
Aarskog-Scott syndrome is an inherited illness that primarily affects males. It occurs for one in one million births. However, mild forms of the disorder do exist and may go unrecognized. The disorder is identified by stunted growth along with facial, genital and skeletal abnormalities.
The syndrome is named after Dagfinn Aarskog, a Norwegian pediatrician and geneticist who first described the syndrome in 1970, and also after Charles I. Scott, Jr., an American geneticist who also noted the syndrome in 1971.
Aarskog-Scott syndrome (AAS) is also called:
• Aarskog disease.
• Aarskog-Scott Syndrome.
• AAS.
• Faciodigitogenital Syndrome.
• Faciogenital Dysplasia.
• FGDY.
• Scott Aarskog syndrome.
Signs and symptoms
The Aarskog-Scott syndrome is a disorder characterized by a set of characteristic facial, genital and skeletal abnormalities including anteverted nostrils, hypertelorism, downslanting palpebral fissures, joint laxity, mental retardation, short stature and shawl scrotum. The physical phenotype of the syndrome varies with age and postpuberal males might only show minor manifestations of the prepuberal phenotype. Female carriers may exhibit mild symptoms.
Mild to moderate growth is evident by one to three years old, accompanied by a delayed growth spurt during adolescence. Mild mental retardation is sometimes present, along with attention deficit disorder and hyperactivity. Despite these factors, social skills are usually normal.
People afflicted with Aarskog syndrome usually have rounded faces with a widow’s peak and ocular hypertelorism (wide set eyes). The eyelids are generally droopy (ptosis) along with palpebral fissures (downward slanting eyelids). The nose has small nostrils that are tipped forward accompanied by a broad nasal bridge. The mid-portion of the face – the maxilla – usually does not develop properly. A broad philtrum – a groove – is present above the top lip and a crease is present below the bottom lip. Teeth eruption is also delayed and there may be underdevelopment of enamel, called enamel hypoplasia. In addition, the top parts of the ear are folded over and the ears may be low set.
In addition to prominent facial features, Aarskog sufferers have a variety of afflictions to other body parts, including:
Broad, small hands and feet accompanied by brachydactyly – short, bulbous toes and fingers – and an in-curved fifth finger, called clinodactyly.
Short neck with webbing at the sides
Roughly 50 percent of Aarskog sufferers have spinal deformities where there is incomplete closure of the spinal column bones (spina bifida occulta). There may also be an underdevelopment of the peglike protrusions on the second cervical vertebra, a condition called odontoid hypoplasia. Pectus excavatum – a sunken chest – is generally mild
Protruding navel and inguinal hernias-- a protrusion of abdominal cavity contents through the inguinal canal (a passage in the lower abdominal wall).
Shawl scrotum – a condition where the skin of the scrotum covers the penis, and one or more undescended testicles. The urinary opening – the meatus – may be located on the undersurface of the penis.
Less common symptoms include: scoliosis – an abnormal curvature of the spinal column; cleft palate; cleft lip; webbed fingers; strabismus (crossed eyes); hyperopia (farsightedness) and some eye muscles may be paralyzed.
Related Disorders
Noonan syndrome is a rare genetic disorder that's often obvious when a child is born. The disorder could be distinguished by a wide range of symptoms and physical features that change seriously in range and extremity.
In numerous affected people, characteristic abnormalities include a particular facial appearance; a broad or webbed neck; a low hairline in the back of the head; and short status. Skeletal malformations are also generally present, for example – breastbone defects, scoliosis or kyphosis (hunchback or slouching posture), elbows that stick out (cubitus valgus).
Many children with Noonan syndrome also have heart defects, such as obstruction of correct blood flow from the lower right chamber of the heart to the lungs (pulmonary valvular stenosis, or PVS). In some people, Noonan syndrome appears to come from sporadic genetic mutations.
Robinow syndrome is a very rare inherited disorder indicated by mild short position due to expansion delays after birth; characteristic disorders of the head and facial area; skeletal malformations; and / or genital disorders.
Skeletal malformations may include radius and ulna bones in the forearm that are short (forearm brachymelia), short toes and fingers, bent 5th fingers (clinodactyly), small hands with broad thumbs, rib malformations, scoliosis, and / or underdevelopment of one side of the bones in the middle (thoracic) piece of the spine (hemivertebrae).
Genital aberrations linked with Robinow syndrome may include a micropenis – an unusually small penis and failure of the testes to descend into the scrotum in males or underdevelopment (hypoplasia) of the clitoris and labia majora in females. The range and seriousness of symptoms differ from case to case.
LEOPARD syndrome is so-named for the acronym that described the disorder:
(L)entigines, black or dark brown spots on the skin that resemble freckles
(E)lectrocardiographic defects, or problems with the electrical activity of the heart
(0)cular hypertelorism – eyes that are widely-spaced
(P)ulmonary stenosis – problems with the flow of blood from the lower right heart ventricle (chamber)
(A)bnormalities in the genital area
(R)etarded growth
(D)eafness or hearing loss
In addition to the above symptoms, LEOPARD Syndrome sufferers may also exhibit mild mental retardation, speech difficulties, or a range of other physical abnormalities. LEOPARD Syndrome occurs apparently at random. However, it is thought to be due to an inherited autosomal dominant trait.
If you think someone in your family may have Aarskog syndrome, you may be able to get genetic testing for FGDY1 gene mutations.
Actual diagnosis for the disorder is made through a detailed patient history and a clinical examination which notes characteristics of the disorder. X-rays may also be useful in identifying certain findings and differentiate the disorder from similar ones.
Treatment
Treatments vary because of the wide range of individual symptoms. Treatment may require a team of specialists including: pediatricians, surgeons, cardiologists, dentists, speech pathologists, audiologists, ophthalmologists and other health care professionals.
Surgery can be performed to correct specific congenital or structural malformations. Surgery can also correct undescended testicles. Orthodontic treatment may correct some facial abnormalities.
Aarskog-Scott syndrome is inherited via an X-linked recessive gene, located at Gene Map Locus Xp11.21. In other words, the syndrome is due to mutation in a gene called FGDY1 in band p11.21 on the X chromosome. Research has also suggested that there is a second type of the disorder which is transmitted as a sex-influenced autosomal dominant trait. Boys of female carriers are at fifty percent likelihood of being influenced with the syndrome. Girls of female carriers are at fifty percent chance of being carriers themselves. Females could have mild manifestations of the syndrome.
The FGD1 gene plays a role in skeletal type cells, including mesenchymal prechondrocytes, chondrocytes, and osteoblasts. Research suggests that the primary defect in Aarskog–Scott syndrome is a FGD1/Cdc42 signaling abnormality, which results in embryonic development issues along with abnormal endochondral and intramembranous bone formation.
Genetic testing (also called DNA-based tests) is among the newest and most sophisticated of techniques[1] used to test for genetic disorders which involves direct examination of the DNA molecule itself. Other genetic tests include biochemical tests for such gene products as enzymesand other proteins and for microscopic examination of stained or fluorescent chromosomes. Genetic tests are used for several reasons, including:
carrier screening, which involves identifying unaffected individuals who carry one copy of a gene for a disease that requires two copies for the disease to be expressed
preimplantation genetic diagnosis
prenatal diagnostic testing
newborn screening
Genealogical DNA test (for genetic genealogy purposes)
presymptomatic testing for predicting adult-onset disorders such as Huntington's disease
presymptomatic testing for estimating the risk of developing adult-onset cancers and Alzheimer's disease
- confirmational diagnosis of a symptomatic individual
forensic/identity testing
Genetic testing allows the genetic diagnosis of vulnerabilities to inherited diseases, and can also be used to determine a child's paternity (genetic father) or a person's ancestry. Normally, every person carries two copies of every gene (with the exception of genes related to sex-linked traits, which are only inherited from the mother by males), one inherited from their mother, one inherited from their father. The human genome is believed to contain around 20,000 - 25,000 genes. In addition to studying chromosomes to the level of individual genes, genetic testing in a broader sense includes biochemical tests for the possible presence of genetic diseases, or mutant forms of genes associated with increased risk of developing genetic disorders. Genetic testing identifies changes in chromosomes, genes, or proteins.[2] Most of the time, testing is used to find changes that are associated with inherited disorders. The results of a genetic test can confirm or rule out a suspected genetic condition or help determine a person's chance of developing or passing on a genetic disorder. Several hundred genetic tests are currently in use, and more are being developed.[3][4]
Since genetic testing may open up ethical or psychological problems, genetic testing is often accompanied by genetic counseling.
Types
Genetic testing is "the analysis of, chromosomes (DNA), proteins, and certain metabolites in order to detect heritable disease-related genotypes, mutations, phenotypes, or karyotypes for clinical purposes."[5] It can provide information about a person's genes and chromosomes throughout life. Available types of testing include:
Newborn screening: Newborn screening is used just after birth to identify genetic disorders that can be treated early in life. The routine testing of infants for certain disorders is the most widespread use of genetic testing—millions of babies are tested each year in the United States. All states currently test infants for phenylketonuria (a genetic disorder that causes mental illness if left untreated) and congenital hypothyroidism (a disorder of the thyroid gland).
Diagnostic testing: Diagnostic testing is used to diagnose or rule out a specific genetic or chromosomal condition. In many cases, genetic testing is used to confirm a diagnosis when a particular condition is suspected based on physical mutations and symptoms. Diagnostic testing can be performed at any time during a person's life, but is not available for all genes or all genetic conditions. The results of a diagnostic test can influence a person's choices about health care and the management of the disease.
Carrier testing: Carrier testing is used to identify people who carry one copy of a gene mutation that, when present in two copies, causes a genetic disorder. This type of testing is offered to individuals who have a family history of a genetic disorder and to people in ethnic groups with an increased risk of specific genetic conditions. If both parents are tested, the test can provide information about a couple's risk of having a child with a genetic condition.
Prenatal testing: Prenatal testing is used to detect changes in a fetus's genes or chromosomes before birth. This type of testing is offered to couples with an increased risk of having a baby with a genetic or chromosomal disorder. In some cases, prenatal testing can lessen a couple's uncertainty or help them decide whether to abort the pregnancy. It cannot identify all possible inherited disorders and birth defects, however.
Preimplantation genetic diagnosis: Genetic testing procedures that are performed on human embryos prior to the implantation as part of an in vitro fertilization procedure.
Predictive and presymptomatic testing: Predictive and presymptomatic types of testing are used to detect gene mutations associated with disorders that appear after birth, often later in life. These tests can be helpful to people who have a family member with a genetic disorder, but who have no features of the disorder themselves at the time of testing. Predictive testing can identify mutations that increase a person's chances of developing disorders with a genetic basis, such as certain types of cancer. For example, an individual with a mutation in BRCA1 has a 65% cumulative risk of breast cancer.[6] Presymptomatic testing can determine whether a person will develop a genetic disorder, such as hemochromatosis (an iron overload disorder), before any signs or symptoms appear. The results of predictive and presymptomatic testing can provide information about a person’s risk of developing a specific disorder and help with making decisions about medical care.