X-ray and neuroimaging studies may be helpful in confirming a diagnosis of Coffin–Lowry syndrome. Decreased ribosomal S6 kinase activity in cultured fibroblast or transformed lymphoblast cells from a male indicates Coffin–Lowry syndrome. Studies of enzyme activity can not be used to diagnose an affected female.

Molecular genetic testing on a blood specimen or cells from a cheek swab is available to identify mutations in the RSK2 gene. This testing can be used to confirm but not rule out the diagnosis of Coffin–Lowry syndrome because not all affected individuals have a detectable mutation.

The diagnosis of Wilson–Turner syndrome is based upon a clinical evaluation, a detailed patient history, and identification of characteristic features. Molecular genetic testing for mutations in the HDAC8 gene is now available to confirm the diagnosis.

The Wilson–Turner syndrome is characterized by mild to moderate range of intellectual disability, obesity, tapered fingers, and mood swings. Males also suffer from gynecomastia and hypogonadism. In order to be diagnosed with Wilson-Turner Syndrome, male patients must suffer from intellectual disability, obesity, and gynecomastia. Females do not necessarily have to have noticeable phenotype but can be diagnosed with this disorder by studying her family history and identifying others with the disorder. It has been noted that children with Wilson-Turner Syndrome will display speech development delay and excessive drooling. Males can be confirmed by testing androgen levels. Female carriers will show silencing of the gene a complex X inactivation.

In a sample of 19 children, a 1997 study found that 3 died before the age of 3, and 2 never learned to walk. The children had various levels of delayed development with developmental quotients from 60 to 85.

The use of biochemical testing for the detection of carriers is technically demanding and not often used. Biochemical analyses that have been performed on hair bulbs from at risk women have had a small number of both false positive and false negative outcomes. If only a suspected carrier female is available for mutation testing, it may be appropriate to grow her lymphocytes in 6-thioguanine (a purine analogue), which allows only HGPRT-deficient cells to survive. A mutant frequency of 0.5–5.0 × 10 is found in carrier females, while a non-carrier female has a frequency of 1–20 × 10. This frequency is usually diagnostic by itself.

Molecular genetic testing is the most effective method of testing, as HPRT1 is the only gene known to be associated with LNS. Individuals who display the full Lesch–Nyhan phenotype all have mutations in the HPRT1 gene. Sequence analysis of mRNA is available clinically and can be utilized in order to detect HPRT1 mutations in males affected with Lesch–Nyhan syndrome. Techniques such as RT-PCR, multiplex genomic PCR, and sequence analysis (cDNA and genomic DNA), used for the diagnosis of genetic diseases, are performed on a research basis. If RT-PCR tests result in cDNA showing the absence of an entire exon or exons, then multiplex genomic PCR testing is performed. Multiplex genomic PCR testing amplifies the nine exons of the HPRT1 gene as eight PCR products. If the exon in question is deleted, the corresponding band will be missing from the multiplex PCR. However, if the exon is present, the exon is sequenced to identify the mutation, therefore causing exclusion of the exon from cDNA. If no cDNA is created by RT-PCR, then multiplex PCR is performed on the notion that most or all of the gene is obliterated.

The assessment for Smith-Finemen-Myers syndrome like any other mental retardation includes a detailed family history and physical exam that tests the mentality of the patient. The patient also gets a brain and skeletal imaging though CT scans or x-rays. They also does a chromosome study and certain other genetic biochemical tests to help figure out any other causes for the mental retardation.

The diagnosis of SFMS is based on visible and measurable symptoms. Until 2000, SFMS was not known to be associated with any particular gene. As of 2001, scientists do not yet know if other genes are involved in this rare disease. Generic analysis of the ATRX gene may prove to be helpful in diagnosis of SFMS.

Due to the wide range of genetic disorders that are presently known, diagnosis of a genetic disorder is widely varied and dependent of the disorder. Most genetic disorders are diagnosed at birth or during early childhood, however some, such as Huntington's disease, can escape detection until the patient is well into adulthood.

The basic aspects of a genetic disorder rests on the inheritance of genetic material. With an in depth family history, it is possible to anticipate possible disorders in children which direct medical professionals to specific tests depending on the disorder and allow parents the chance to prepare for potential lifestyle changes, anticipate the possibility of stillbirth, or contemplate termination. Prenatal diagnosis can detect the presence of characteristic abnormalities in fetal development through ultrasound, or detect the presence of characteristic substances via invasive procedures which involve inserting probes or needles into the uterus such as in amniocentesis.

There is no cure and no standard course of treatment for Coffin–Lowry syndrome. Treatment is symptomatic and supportive, and may include occupational, physical and speech therapy and educational services.

Since the symptoms caused by this disease are present at birth, there is no “cure.” The best cure that scientists are researching is awareness and genetic testing to determine risk factors and increase knowledgeable family planning. Prevention is the only option at this point in time for a cure.

Not all genetic disorders directly result in death, however there are no known cures for genetic disorders. Many genetic disorders affect stages of development such as Down syndrome. While others result in purely physical symptoms such as muscular dystrophy. Other disorders, such as Huntington's disease show no signs until adulthood. During the active time of a genetic disorder, patients mostly rely on maintaining or slowing the degradation of quality of life and maintain patient autonomy. This includes physical therapy, pain management, and may include a selection of alternative medicine programs.

Cytogenetic analysis for fragile X syndrome was first available in the late 1970s when diagnosis of the syndrome and carrier status could be determined by culturing cells in a folate deficient medium and then assessing for "fragile sites" (discontinuity of staining in the region of the trinucleotide repeat) on the long arm of the X chromosome. This technique proved unreliable, however, as the fragile site was often seen in less than 40% of an individual's cells. This was not as much of a problem in males, but in female carriers, where the fragile site could generally only be seen in 10% of cells, the mutation often could not be visualised.

Since the 1990s, more sensitive molecular techniques have been used to determine carrier status. The fragile X abnormality is now directly determined by analysis of the number of CGG repeats using polymerase chain reaction (PCR) and methylation status using Southern blot analysis. By determining the number of CGG repeats on the X chromosome, this method allows for more accurate assessment of risk for premutation carriers in terms of their own risk of fragile X associated syndromes, as well as their risk of having affected children. Because this method only tests for expansion of the CGG repeat, individuals with FXS due to missense mutations or deletions involving "FMR1" will not be diagnosed using this test and should therefore undergo sequencing of the FMR1 gene if there is clinical suspicion of FXS.

Prenatal testing with chorionic villus sampling or amniocentesis allows diagnosis of FMR1 mutation while the fetus is in utero and appears to be reliable.

Early diagnosis of fragile X syndrome or carrier status is important for providing early intervention in children or fetuses with the syndrome, and allowing genetic counselling with regards to the potential for a couple's future children to be affected. Most parents notice delays in speech and language skills, difficulties in social and emotional domains as well as sensitivity levels in certain situations with their children.

The urate to creatinine (breakdown product of creatine phosphate in muscle) concentration ratio in urine is elevated. This is a good indicator of acid overproduction. For children under ten years of age with LNS, a urate to creatinine ratio above two is typically found. Twenty-four-hour urate excretion of more than 20 mg/kg is also typical but is not diagnostic. Hyperuricemia (serum uric acid concentration of >8 mg/dL) is often present but not reliable enough for diagnosis. Activity of the HGPRT enzyme in cells from any type of tissue (e.g., blood, cultured fibroblasts, or lymphoblasts) that is less than 1.5% of normal enzyme activity confirms the diagnosis of Lesch–Nyhan syndrome. Molecular genetic studies of the HPRT gene mutations may confirm diagnosis, and are particularly helpful for subsequent 'carrier testing' in at-risk females such as close family relatives on the female side.

The disorder is characterized by absence or underdevelopment of the cerebellar vermis and a malformed brain stem (molar tooth sign), both of which can be visualized on a MRI scan. Together with this sign, the diagnosis is based on the physical symptoms and genetic testing for mutations. If the gene mutations have been identified in a family member, prenatal or carrier diagnosis can be pursued.

Joubert Syndrome is known to affect 1 in 80,000-100,000 newborns. Due to the variety of genes this disorder is affected by, it is likely to be under-diagnosed. It is commonly found in Ashkenazi Jewish, French-Canadians, and Hutterite ethnic populations. Most cases of Joubert syndrome are autosomal recessive - in these cases, both parents are either carriers or affected. Rarely, Joubert syndrome is inherited in an X-linked recessive pattern. In these cases, males are more commonly affected because affected males must have one X chromosome mutated, while affected females must have mutated genes on both X chromosomes.

XLI can be suspected based on clinical findings, although symptoms can take varying amounts of time to become evident, from a few hours after birth, up to a year in milder cases. The diagnosis is usually made by a dermatologist, who also typically formulates the treatment plan (see below). STS enzyme deficiency is confirmed using a clinically available biochemical assay. Carrier detection can be performed in mothers of affected sons using this test (see Genetics, below). Molecular testing for DNA deletions or mutations is also offered, and can be particularly useful in the evaluation of individuals with associated medical conditions (see below). Prenatal diagnosis is possible using either biochemical or molecular tests. However, the use of prenatal diagnosis for genetic conditions that are considered to be generally benign raises serious ethical considerations and requires detailed genetic counseling.

Because the variability of this disease is so great and the way that it reveals itself could be multi-faceted; once diagnosed, a multidisciplinary team is recommended to treat the disease and should include a craniofacial surgeon, ophthalmologist, pediatrician, pediatric urologist, cardiologist, pulmonologist, speech pathologist, and a medical geneticist. Several important steps must be followed, as well.

- Past medical history

- Physical examination with special attention to size and measurements of facial features, palate, heart, genitourinary system and lower respiratory system

- Eye evaluation

- Hypospadias assessment by urologist

- Laryngoscopy and chest x-ray for difficulties with breathing/swallowing

- Cleft lip/palate assessment by craniofacial surgeon

- Assessment of standard age developmental and intellectual abilities

- Anal position assessment

- Echocardiogram

- Cranial imaging

Many surgical repairs may be needed, as assessed by professionals. Furthermore, special education therapies and psychoemotional therapies may be required, as well. In some cases, antireflux drugs can be prescribed until risk of breathing and swallowing disorders are removed. Genetic counseling is highly advised to help explain who else in the family may be at risk for the disease and to help guide family planning decisions in the future.

Because of its wide variability in which defects will occur, there is no known mortality rate specifically for the disease. However, the leading cause of death for people with Opitz G/BBB syndrome is due to infant death caused by aspiration due to esophageal, pharyngeal or laryngeal defects.

Fortunately, to date there are no factors that can increase the expression of symptoms of this disease. All abnormalities and symptoms are present at birth.

Management of AIS is currently limited to symptomatic management; no method is currently available to correct the malfunctioning androgen receptor proteins produced by "AR" gene mutations. Areas of management include sex assignment, genitoplasty, gonadectomy in relation to tumor risk, hormone replacement therapy, genetic counseling, and psychological counseling.

The diagnosis is made on the basis of clinical parameters, the peripheral blood smear, and low immunoglobulin levels. Typically, IgM levels are low, IgA levels are elevated, and IgE levels may be elevated; paraproteins are occasionally observed. Skin immunologic testing (allergy testing) may reveal hyposensitivity. Not all patients have a positive family history of the disorder; new mutations do occur. Often, leukemia may be suspected on the basis of low platelets and infections, and bone marrow biopsy may be performed. Decreased levels of Wiskott-Aldrich syndrome protein and/or confirmation of a causative mutation provides the most definitive diagnosis.

Sequence analysis can detect the WAS-related disorders of Wiskott–Aldrich syndrome, XLT, and XLN. Sequence analysis of the "WASp" gene can detect about 98% of mutations in males and 97% of mutations in female carriers. Because XLT and XLN symptoms may be less severe than full WAS and because female carriers are usually asymptomatic, clinical diagnosis can be elusive. In these cases, genetic testing can be instrumental in diagnosis of WAS-related disorders.

Trisomy 9 can be detected prenatally with chorionic villus sampling and cordocentesis, and can be suggested by obstetric ultrasonography.

Because trisomy 9 may appear with mosaicism, it is suggested that doctors take samples from multiple tissues when karyotyping for diagnosis.

Preimplantation genetic diagnosis (PGD or PIGD) refers to genetic profiling of embryos prior to implantation (as a form of embryo profiling), and sometimes even of oocytes prior to fertilization. When used to screen for a specific genetic sequence, its main advantage is that it avoids selective pregnancy termination, as the method makes it highly likely that a selected embryo will be free of the condition under consideration.

In the UK, AIS appears on a list of serious genetic diseases that may be screened for via PGD. Some ethicists, clinicians, and intersex advocates have argued that screening embryos to specifically exclude intersex traits are based on social and cultural norms as opposed to medical necessity.

Courses of treatment for children with is dependent upon the severity of their case. Children with OHS often receive physical and occupational therapy. They may require a feeding tube to supplement nourishment if they are not growing enough. In an attempt to improve the neurological condition (seizures) copper histidine or copper chloride injections can be given early in the child’s life.

However, copper histidine injections have been shown ineffective in studies of copper metabolic-connective tissue disorders such as OHS.

The clinical presentation of ALD can vary greatly, making diagnosis difficult. With the variety of phenotypes, clinical suspicion of ALD can result from a variety of different presentations. Symptoms vary based on the disease phenotype, and even within families or between twins. When ALD is suspected based on clinical symptoms, the initial testing usually includes plasma very long chain fatty acid (VLCFA) determination using gas chromatography-mass spectrometry. The concentration of unsaturated VLCFA, particularly 26 carbon chains is significantly elevated in males with ALD, even prior to the development of other symptoms. Confirmation of ALD after positive plasma VLCFA determination usually involves molecular genetic analysis of "ABCD1". In females, where plasma VLCFA measurement is not always conclusive (some female carriers will have normal VLCFA in plasma), molecular analysis is preferred, particularly in cases where the mutation in the family is known. Although the clinical phenotype is highly variable among affected males, the elevations of VLCFA are present in all males with an "ABCD1" mutation.

Because the characteristic elevations associated with ALD are present at birth, well before any symptoms are apparent, there have been methods developed in the interests of including it in newborn screening programs. One of the difficulties with ALD as a disease included in universal newborn screening is the difficulty in predicting the eventual phenotype that an individual will express. The accepted treatment for affected boys presenting with the cerebral childhood form of the disease is a bone marrow transplant, a procedure which carries significant risks. However, because most affected males will demonstrate adrenal insufficiency, early discovery and treatment of this symptom could potentially prevent complications and allow these patients to be monitored for other treatment in the future, depending on the progression of their disease.

The Loes score is a rating of the severity of abnormalities in the brain found on MRI. It ranges from 0 to 34, based on a point system derived from the location and extent of disease and the presence of atrophy in the brain, either localized to specific points or generally throughout the brain. A Loes score of 0.5 or less is classified as normal, while a Loes score of 14 or greater is considered severe. It was developed by neuroradiologist Daniel J. Loes MD and is an important tool in assessing disease progression and the effectiveness of therapy.

In May 2013, the US FDA granted Orphan drug status to Diiodothyropropionic acid (DITPA) in the treatment of MCT8 deficiency. This was following the use of DITPA towards a child in Australia, under compassionate grounds.

There is no established treatment for AHDS. Theoretical considerations suggested TRIAC (triiodothyroacetate or tiratricol, a natural non-classical thyroid hormone) to be beneficial. In 2014, a case was demonstrated in which therapy with TRIAC in early childhood led to significant improvement of cognition and mobility. Currently, the effect of Triac is under investigation.

Individuals with CAIS are raised as females. They are born phenotypically female and almost always have a heterosexual female gender identity; the incidence of homosexuality in women with CAIS is thought to be less than unaffected women. However, at least two case studies have reported male gender identity in individuals with CAIS.

CAIS can only be diagnosed in normal phenotypic females. It is not usually suspected unless the menses fail to develop at puberty, or an inguinal hernia presents during premenarche. As many as 1–2% of prepubertal girls that present with an inguinal hernia will also have CAIS.

A diagnosis of CAIS or Swyer syndrome can be made in utero by comparing a karyotype obtained by amniocentesis with the external genitalia of the fetus during a prenatal ultrasound. Many infants with CAIS do not experience the normal, spontaneous neonatal testosterone surge, a fact which can be diagnostically exploited by obtaining baseline luteinizing hormone and testosterone measurements, followed by a human chorionic gonadotropin (hGC) stimulation test.

The main differentials for CAIS are complete gonadal dysgenesis (Swyer syndrome) and Müllerian agenesis (Mayer-Rokitansky-Kuster-Hauser syndrome or MRKH). Both CAIS and Swyer syndrome are associated with a 46,XY karyotype, whereas MRKH is not; MRKH can thus be ruled out by checking for the presence of a Y chromosome, which can be done either by fluorescence in situ hybridization (FISH) analysis or on full karyotype. Swyer syndrome is distinguished by poor breast development and shorter stature. The diagnosis of CAIS is confirmed when androgen receptor (AR) gene sequencing reveals a mutation, although up to 5% of individuals with CAIS do not have an AR mutation.

Up until the 1990s, a CAIS diagnosis was often hidden from the affected individual and / or family. It is current practice to disclose the genotype at the time of diagnosis, particularly when the affected girl is at least of adolescent age. If the affected individual is a child or infant, it is generally up to the parents, often in conjunction with a psychologist, to decide when to disclose the diagnosis.

Treatments are usually based on the individuals symptoms that are displayed. The seizures are controlled with anticonvulsant medication. For the behavior problems, the doctors proscribe to a few medications and behavioral modification routines that involve therapists and other types of therapy. Even if mental retardation is severe, it does not seem to shorten the lifespan of the patient or to get worse with age.