Diagnosis is usually based on clinical findings, although fetal chromosome testing will show trisomy 13. While many of the physical findings are similar to Edwards syndrome there are a few unique traits, such as polydactyly. However, unlike Edwards syndrome and Down syndrome, the quad screen does not provide a reliable means of screening for this disorder. This is due to the variability of the results seen in fetuses with Patau.

Diagnosis often can be made through clinical examination and urine tests (excess mucopolysaccharides are excreted in the urine). Enzyme assays (testing a variety of cells or body fluids in culture for enzyme deficiency) are also used to provide definitive diagnosis of one of the mucopolysaccharidoses. Prenatal diagnosis using amniocentesis and chorionic villus sampling can verify if a fetus either carries a copy of the defective gene or is affected with the disorder. Genetic counseling can help parents who have a family history of the mucopolysaccharidoses determine if they are carrying the mutated gene that causes the disorders.

A large British study from 2008 found a median estimated life expectancy of 11.6 years.

Screening for melanoma in FAMMM kindreds should begin at age 10 with a baseline total body skin examination including scalp, eyes, oral mucosa, genital area, and nail, as family members may develop melanoma in their early teens.

At Mayo Clinic, FAMMM patients with a confirmed mutation and family history of pancreatic cancer are offered screening with either high-resolution pancreatic protocol CT, MRI, or endoscopic ultrasound starting at age 50 or 10 years younger than the earliest family member with pancreas cancer. They are counseled on the lack of evidence-based data to support screening, and on the limitations of our current technology to detect a lesion at a stage amenable to therapy.

More than 80% of children with Patau syndrome die within the first year of life. Children with the mosaic variation are usually affected to a lesser extent. In a retrospective Canadian study of 174 children with trisomy 13, median survival time was 12.5 days. One and ten year survival was 19.8% and 12.9% respectively.

A 1994 review of 150 cases reported in the literature found that 38% had died with a mean age of death of 2 years. 32% were still alive at the time of the report with a mean age of 4.65. No data were available for the remainder. The author described living with DDS as "walking a multidimensional tight rope".

In terms of genetic testing, while it is done for "type 1" of this condition, "type 2" will only render (or identify) those genes which place the individual at higher risk. Other methods/exam to ascertain if an individual has autoimmune polyendocrine syndrome type 2 are:

- CT scan

- MRI

- Ultrasound

Management of autoimmune polyendocrine syndrome type 2 consists of the following:

Galloway Mowat syndrome is a very rare autosomal recessive genetic disorder, consisting of a variety of features including hiatal hernia, microcephaly and nephrotic syndrome.

Wolf–Hirschhorn syndrome is a microdeletion syndrome caused by a deletion within HSA band 4p16.3 of the short arm of chromosome 4, particularly in the region of and . About 87% of cases represent a "de novo" deletion, while about 13% are inherited from a parent with a chromosome translocation. In the cases of familial translocation, there is a 2 to 1 excess of maternal transmission. Of the "de novo" cases, 80% are paternally derived. Severity of symptoms and expressed phenotype differ based on the amount of genetic material deleted. The critical region for determining the phenotype is at 4p16.3 and can often be detected through genetic testing and fluorescence in situ hybridization (FISH). Genetic testing and genetic counseling is offered to affected families.

The exact genetic defect in Galloway Mowat syndrome is yet to be discovered. However, mutations in podocyte proteins, such as nephrin, alpha-actinin 4, and podocin, are associated with proteinuria and nephrotic syndrome. There is reduced expression of synaptopodin, GLEPP1, and nephrin in Galloway-Mowat syndrome, but these are likely secondary to the proteinuria, likely not the proteins mutated in Galloway-Mowat syndrome.

The biochemical lesion appears to be in the Kinase, Endopeptidase and Other Proteins of small Size (KEOPS)/Endopeptidase-like and Kinase associated to transcribed Chromatin (EKC) (KEOPS/EKC) complex. Sequencing of genes in 37 cases of this condition revealed muations in the OSGEP, TP53RK, TPRKB and LAGE3 genes all of which encode subunits in the KEOPS complex. Members of this complex are found in bacteria, archaea and eukaryotes and are highly conserved. The function of this complex is still under investigation.

One Finnish study which followed 25 cases from 18 families found that half the infants died within 3 days of birth and the other half died before 4 months of age.

Raine syndrome (RNS), also called osteosclerotic bone dysplasia, is a rare autosomal recessive congenital disorder characterized by craniofacial anomalies including microcephaly, noticeably low set ears, osteosclerosis, a cleft palate, gum hyperplasia, a hypoplastic nose, and eye proptosis. It is considered to be a lethal disease, and usually leads to death within a few hours of birth. However, a recent report describes two studies in which children with Raine Syndrome have lived to 8 and 11 years old, so it is currently proposed that there is a milder expression that the phenotype can take (Simpson 2009).

It was first characterized in 1989 in a report that was published on an infant that had been born with an unknown syndrome, that later came to be called Raine Syndrome.

The current research describes Raine Syndrome as a neonatal osteosclerotic bone dysplasia, indicated by its osteosclerotic symptoms that are seen in those suffering from the disease. It has been found that a mutation in the gene FAM20C is the cause of the Raine Syndrome phenotype. This microdeletion mutation leads to an unusual chromosome 7 arrangement. The milder phenotypes of Raine Syndrome, such as those described in Simpson’s 2007 report, suggest that Raine Syndrome resulting from missense mutations may not be as lethal as the other described mutations (OMIM). This is supported by findings from Fradin et al. (2011), who reported on children with missense mutations to FAM20C and lived to ages 1 and 4 years, relatively much longer than the life spans of the previously reported children. Simpson et al.’s (2007) report states that to date, effected individuals have had chromosome 7 uniparental isodisomy and a 7p telomeric microdeletion. They had abnormal chromosome 7 arrangements, with microdeletions of their D7S2477 and D7S1484 markers (Simpson 2007).

Raine Syndrome appears to be an autosomal recessive disease. There are reports of recurrence in children born of the same parents, and an increased occurrence in children of closely related, genetically similar parents. Individuals with Raine Syndrome were either homozygous or compound heterozygous for the mutation of FAM20C. Also observed have been nonsynonomous mutation and splice-site changes (Simpson et al. 2007).

FAM20C, located on chromosome 7p22.3, is an important molecule in bone development. Studies in mice have demonstrated its importance in the mineralization of bones in teeth in early development (OMIM, Simpson et al. 2007, Wang et al. 2010). FAM20C stands for “family with sequence similarity 20, member C.” It is also commonly referred to as DMP-4. It is a Golgi-enriched fraction casein kinase and an extracellular serine/threonine protein kinase. It is 107,743 bases long, with 10 exons and 584 amino acids (Weizmann Institute of Science).

Dubin–Johnson syndrome is similar to Rotor syndrome, but can be differentiated by:

Wolf–Hirschhorn syndrome (WHS), also known as chromosome deletion Dillan 4p syndrome, Pitt–Rogers–Danks syndrome (PRDS) or Pitt syndrome, was first described in 1961 by Americans Herbert L. Cooper and Kurt Hirschhorn and, thereafter, gained worldwide attention by publications by the German Ulrich Wolf, and Hirschhorn and their co-workers, specifically their articles in the German scientific magazine "Humangenetik". It is a characteristic phenotype resulting from a partial deletion of chromosomal material of the short arm of chromosome 4 (del(4p16.3)).

The diagnosis of PPS has been made in several ethnic groups, including Caucasian, Japanese, and sub-Saharan African. Males and females are equally likely to suffer from the syndrome. Since the disorder is very rare, its incidence rate is difficult to estimate, but is less than 1 in 10,000.

McKusick–Kaufman syndrome is a genetic condition associated with MKKS.

The condition is named for Dr. Robert L. Kaufman and Victor McKusick. It is sometimes known by the abbreviation MKS. In infancy it can be difficult to distinguish between MKS and the related Bardet–Biedl syndrome, as the more severe symptoms of the latter condition rarely materialise before adulthood.

GRACILE syndrome is a very rare autosomal recessive genetic disorder, one of the Finnish heritage diseases. It is caused by mutation in BCS1L gene that occurs in at least 1 out of 47,000 live births in Finnish people.

GRACILE is an acronym for growth retardation, amino aciduria (amino acids in the urine), cholestasis, iron overload, lactic acidosis, and early death. Other names for this syndrome include Finnish lethal neonatal metabolic syndrome (FLNMS); lactic acidosis, Finnish, with hepatic hemosiderosis; and Fellman syndrome.

Prognosis is good, and treatment of this syndrome is usually unnecessary. Most patients are asymptomatic and have normal lifespans. Some neonates present with cholestasis. Hormonal contraceptives and pregnancy may lead to overt jaundice and icterus (yellowing of the eyes and skin).

Because MOMO is such a rare disorder, very few studies have been conducted into its causes. Current research suggests that it is linked to a de novo (new) autosomal dominant mutation.

Denys–Drash syndrome (DDS) or Drash syndrome is a rare disorder or syndrome characterized by gonadal dysgenesis, nephropathy, and Wilms' tumor.

Clinically, McKusick–Kaufman syndrome is characterized by a combination of three features: postaxial polydactyly, heart defects, and genital abnormalities:

- Vaginal atresia with hydrometrocolpos

- Double vagina and/or uterus.

- Hypospadias, chordee (a downward-curving penis), and undescended testes (cryptorchidism).

- ureter stenosis or ureteric atresia

Worth syndrome is caused by a mutation in the LRP5 gene, located on human chromosome 11q13.4. The disorder is inherited in an autosomal dominant fashion. This indicates that the defective gene responsible for a disorder is located on an autosome (chromosome 11 is an autosome), and only one copy of the defective gene is sufficient to cause the disorder, when inherited from a parent who has the disorder.

Treatment is usually supportive treatment, that is, treatment to reduce any symptoms rather than to cure the condition.

- Enucleation of the odontogenic cysts can help, but new lesions, infections and jaw deformity are usually a result.

- The severity of the basal-cell carcinoma determines the prognosis for most patients. BCCs rarely cause gross disfigurement, disability or death .

- Genetic counseling

Immunohistochemistry is now being used more often to diagnose patients likely to have Muir–Torre syndrome. Sebaceous neoplasms are only infrequently encountered, and immunohistochemistry is reliable and readily available, so researchers have recommended its use. Routine immunohistochemical detection of DNA mismatch repair proteins help identify hereditary DNA mismatch repair deficiency.

Treatment of Muir–Torre syndrome normally consists of oral isotretinoin. The drug has been found to prevent tumor development.

Patients with Muir–Torre syndrome should follow the same stringent screening for colorectal carcinoma and other malignancies as patients with Lynch syndrome. This includes frequent and early colonoscopies, mammograms, dermatologic evaluation, and imaging of the abdomen and pelvis.