Symptoms begin in infancy and include:

- hypotonia

- areflexia

- amyotrophy

- variable degrees of dysgenesis of the corpus callosum

- mild to severe intellectual and developmental delay

- psychiatric problems including paranoid delusions, depression, hallucinations and autistic-like behavior

It causes facial abnormalities, skeletal malformation and occasionally neural tube defects; the skeletal disfigurements resolve to a degree in the course of development.

Mutations in different parts of the gene may lead to deafness or Stickler syndrome type III (eye problems: myopia, retinal detachment and skeletal abnormalities).

Infants and children: Infants that are born with Weissenbacher-Zweymüller syndrome usually have short bones in their arms and legs. The thigh and upper arm bones are wider than usual resulting in a dumbbell-shape while the bones of the vertebrae may be abnormal. Typical abnormal facial features can be wide-set protruding eyes (hypertelorism), a small and upturned nose with a flat bridge, small jaw (micrognathia) and a cleft palate. Some infants have high-frequency hearing loss. Infants may also exhibit a psychomotor delay. After the period of growth deficiency the individual makes improvements in bone growth leading to a normal physical development around age 5 or 6.

Adults: Many with Weissenbacher-Zweymüller syndrome have a catch-up growth phase causing the adults to not be unusually short. Many adults still will have hearing loss and typical abnormal facial features of Weissenbacher-Zweymüller syndrome.

Andermann syndrome also known as agenesis of corpus callosum with neuronopathy (ACCPN), Charlevoix disease among others is a very rare neurodegenerative genetic disorder that damages the nerves used to control muscles and related to sensation, and is often associated with agenesis of the corpus collosum.

It was first described by Eva Andermann et al. in 1972.

Weissenbacher–Zweymuller syndrome (WZS), also called Pierre-Robin syndrome with fetal chondrodysplasia, is an autosomal recessive congenital disorder, linked to mutations (955 gly -> glu) in the "COL11A2" gene (located on chromosomal position 6p21.3), which codes for the α strand of collagen type XI. It is a collagenopathy, types II and XI disorder.

The signs and symptoms of this condition are consistent with the following{it should be noted that possible complications include aortic stenosis and hearing loss):

Acrodysostosis also known as Arkless-Graham syndrome or Maroteaux-Malamut syndrome is a rare congenital malformation syndrome which involves shortening of the interphalangeal joints of the hands and feet, intellectual disability in approximately 90% of affected children, and peculiar facies. Other common abnormalities include short head (as measured front to back), small broad upturned nose with flat nasal bridge, protruding jaw, increased bone age, intrauterine growth retardation, juvenile arthritis and short stature. Further abnormalities of the skin, genitals, teeth, and skeleton may occur.

Most reported cases have been sporadic, but it has been suggested that the condition might be genetically related i.e. in an autosomal dominant mode of transmission. Both males and females are affected. The disorder has been associated with the older age of parents at the time of conception.

A PRKAR1A mutation has been identified in acrodysostosis with hormone resistance.

Buschke–Ollendorff syndrome, also known as dermatofibrosis lenticularis disseminata, is a rare genetic disorder associated with LEMD3. It is believed to be inherited in an autosomal dominant manner.It is named for Abraham Buschke and Helene Ollendorff Curth who described it in a 45-year-old woman. Its frequency is almost 1 case per every 20,000 people and is equally found in both males and females.

The sarcoglycanopathies are a collection of diseases resulting from mutations in any of the five sarcoglycan genes: α, β, γ, δ or ε.

The five sarcoglycanopathies are: α-sarcoglycanopathy, LGMD2D; β-sarcoglycanopathy, LGMD2E; γ-sarcoglycanopathy, LGMD2C; δ-sarcoglycanopathy, LGMD2F and ε-sarcoglycanopathy, myoclonic dystonia. The four different sarcoglycan genes encode proteins that form a tetrameric complex at the muscle cell plasma membrane. This complex stabilizes the association of dystrophin with the dystroglycans and contributes to the stability of the plasma membrane cytoskeleton. The four sarcoglycan genes are related to each other structurally and functionally, but each has a distinct chromosome location.

In outbred populations, the relative frequency of mutations in the four genes is alpha » beta » gamma » delta in an 8:4:2:1 ratio. No common mutations have been identified in outbred populations except the R77C mutation, which accounts for up to one-third of the mutated SGCA alleles. Founder mutations have been observed in certain populations. A 1997 Italian clinical study demonstrated variations in muscular dystrophy progression dependent on the sarcoglycan gene affected.

This disorder is present at birth, however, it may not be understood until several years after birth. Acrodysostosis affects males and females in almost similar numbers. It is difficult to determine the frequency of acrodysostosis in the population as many cases of this disorder cannot be diagnosed properly.

Other common links between people with TAR seem to include anemia, heart problems, kidney problems, knee joint problems, frequently lactose intolerance.

Different cases with leukemia in patients with TAR are described in.

TAR Syndrome (thrombocytopenia with absent radius) is a rare genetic disorder that is characterized by the absence of the radius bone in the forearm and a dramatically reduced platelet count.

About 10–15% of human couples are infertile, unable to conceive. In approximately in half of these cases, the underlying cause is related to the male. The underlying causative factors in the male infertility can be attributed to environmental toxins, systemic disorders such as, hypothalamic–pituitary disease, testicular cancers and germ-cell aplasia. Genetic factors including aneuploidies and single-gene mutations are also contributed to the male infertility. Patients suffering from nonobstructive azoospermia or oligozoospermia show microdeletions in the long arm of the Y chromosome and/or chromosomal abnormalities, each with the respective frequency of 9.7% and 13%. A large percentage of human male infertility is estimated to be caused by mutations in genes involved in primary or secondary spermatogenesis and sperm quality and function. Single-gene defects are the focus of most research carried out in this field.

NR5A1 mutations are associated with male infertility, suggesting the possibility that these mutations cause the infertility. However, it is possible that these mutations individually have no major effect and only contribute to the male infertility by collaboration with other contributors such as environmental factors and other genomics variants. Vice versa, existence of the other alleles could reduce the phenotypic effects of impaired NR5A1 proteins and attenuate the expression of abnormal phenotypes and manifest male infertility solely.

Mevalonate kinase deficiency, also called mevalonic aciduria and hyper immunoglobin D syndrome is an autosomal recessive metabolic disorder that disrupts the biosynthesis of cholesterol and isoprenoids.

It is characterized by an elevated level of immunoglobin D in the blood.

The enzyme is involved in biosynthesis of cholesterols and isoprenoids. The enzyme is necessary for the conversion of mevalonate to mevalonate-5-phosphate in the presence of Mg2+ [Harper’s biochemistry manual]. Mevalonate kinase deficiency causes the accumulation of mevalonate in urine and hence the activity of the enzyme is again reduced Mevalonate kinase deficiency. It was first described as HIDS in 1984.

Mevalonate kinase deficiency causes an accumulation of mevalonic acid in the urine, resulting from insufficient activity of the enzyme mevalonate kinase (ATP:mevalonate 5-phosphotransferase; EC 2.7.1.36).

The disorder was first described in 1985.

Classified as an inborn error of metabolism, mevalonate kinase deficiency usually results in developmental delay, hypotonia, anemia, hepatosplenomegaly, various dysmorphic features, mental retardation, an overall failure to thrive and several other features.

Fields' disease is considered to be one of the rarest known diseases in the world, with only two diagnosed cases in history. The frequency of this disease is therefore 1 in approximately 3.75 billion (although since the disease manifested in identical twins, the actual frequency is 1 in approximately 7.5 billion). It is named after Welsh twins Catherine and Kirstie Fields, of Llanelli. Fields' disease is a neuromuscular disease, causing muscular degeneration.

The disease was first noticed when the twins were around the age of four. Doctors have been unable to identify it and have not been able to match it to any known diseases. As a result, the Fields sisters have undergone numerous tests, but no treatment has yet been found. No definitive cause has been determined and doctors have generally concluded that they were born with it.

The disease appears to be progressive in nature. The Fields twins started having problems when they were four years old. By the time they had reached the age of nine, they were having difficulty walking and needed frames to assist them with walking. Their muscles have been gradually deteriorating over time. The disease affects the twins' nerves, causing them to make involuntary muscle movements such as trembling in the hands.

The extent of the disease is still unknown as the two women are only 21. However, the disease has had no apparent effect on their brains or personalities. Doctors do not know if the disease is fatal and, if so, what the life expectancy of one with this disease is. If the cause of the disease is genetic, there is a chance that the twins could pass it on to their future children.

MBL deficiency refers to Mannan-binding lectin pathway components such as MBL2.

It is thought that 5-10% of the population have an MBL deficiency of some degree There are varying degrees of MBL deficiency; some people in a given population will not even know they have the deficiency, while others may have such low levels that they experience infections with great frequency. Babies and young children are most at risk.

Northern epilepsy syndrome or progressive epilepsy with mental retardation (EPMR) is a subtype of neuronal ceroid lipofuscinosis and a rare disease that is regarded as a Finnish heritage disease. Unlike most Finnish heritage diseases, this syndrome has been reported only in Finland.

The disease is characterized by seizures in early childhood that progressively get worse until after puberty. Once the onset of seizures occurs, mental degradation is seen. This continues into adulthood even after seizure frequency has decreased. The cause of the disease is a missense mutation in chromosome 8. The creation of a new protein occurs and the lipid content of the brain is altered because of it. The ratio of the mutation carriers is 1:135. There is nothing that has been found to stop the progression of the disease, but symptomatic approaches, such as the use of benzodiazepines, have helped control seizures.

Northern Epilepsy Syndrome causes recurrent seizures between the ages of five to ten. These seizures, that may last up to 15 minutes, can be classified mostly as tonic-clonic, but partial seizures could also occur. The seizures commonly involve muscle rigidity, convulsions, and loss of consciousness. Generally, the recurrence is one to two times per month.

In the years following the onset of seizures, a noticeable decrease in intellectual capacity is observed.

Dermatosis papulosa nigra (DPN) is a condition of many small, benign skin lesions on the face, a condition generally presenting on dark-skinned individuals. DPN is extremely common, affecting up to 30% of Black people in the US. From a histological perspective, DPN resembles seborrheic keratoses. The condition may be cosmetically undesirable to some.

They should not be confused for Leser-Trélat sign, a sudden explosion of lesions due to a growing tumor.

DPN is benign and not associated with any mortality or morbidity.

Nuclear receptor subfamily 5 group A member 1 (NR5A1), also known as SF1 or Ad4BP (MIM 184757), is located on the long arm of chromosome 9 (9q33.3). The NR5A1 is an orphan nuclear receptor that was first identified following the search for a common regulator of the cytochrome P450 steroid hydroxylase enzyme family. This receptor is a pivotal transcriptional regulator of an array of genes involved in reproduction, steroidogenesis and male sexual differentiation and also plays a crucial role in adrenal gland formation in both sexes. NR5A1 regulates the mullerian inhibitory substance by binding to a conserved upstream regulatory element and directly participates in the process of mammalian sex determination through mullerian duct regression. Targeted disruption of NR5A1 (Ftzf1) in mice results in gonadal and adrenal agenesis, persistence of Mullerian structures and abnormalities of the hypothalamus and pituitary gonadotropes. Heterozygous animals demonstrate a milder phenotype including an impaired adrenal stress response and reduced testicular size. In humans, NR5A1 mutations were first described in patients with 46, XY karyotype and disorders of sex development (DSD), Mullerian structures and primary adrenal failure (MIM 612965). After that, heterozygous NR5A1 mutations were described in seven patients showing 46, XY karyotype and ambiguous genitalia, gonadal dysgenesis, but no adrenal insufficiency. Since then, studies have confirmed that mutations in NR5A1 in patients with 46, XY karyotype cause severe underandrogenisation, but no adrenal insufficiency, establishing dynamic and dosage-dependent actions for NR5A1. Subsequent studies revealed that NR5A1 heterozygous mutations cause primary ovarian insufficiency (MIM 612964).

Atrophia Maculosa Varioliformis Cutis (AMVC) is a condition involving spontaneous scarring, specifically depressed scars on the face occurring over a period of months to years. It appears to only affect children and young adults, is considered to be quite rare, normally occurs on the cheeks, temple area and forehead, and is not well understood nor presently treatable. Case reports indicate the scars deepen over time but remain relatively superficial, and with the frequency of new scar appearance diminishing over time.

AMVC is quite difficult to diagnose, for reasons including the depressed box and ice pick scars being very similar to that caused by Acne vulgaris. A confident diagnosis can be made if such scars recently appeared without present acne and without a history of acne. Otherwise the correct diagnosis is usually not made, and even doing so provides little benefit as there is no treatment. It has been suggested in case reports that the condition, although rare, is likely underreported.

Harding ataxia, also known as Early onset cerebellar ataxia with retained reflexes (EOCARR), is an autosomal recessive cerebellar ataxia originally described by Harding in 1981. This form of cerebellar ataxia is similar to Friedreich ataxia including that it results in poor reflexes and balance, but differs in several ways, including the absence of diabetes mellitus, optic atrophy, cardiomyopathy, skeletal abnormalities, and the fact that tendon reflexes in the arms and knees remain intact. This form of ataxia is characterized by onset in the first 20 years, and is less severe than Friedreich ataxia. Additional cases were diagnosed in 1989, 1990, 1991, and 1998.

SCA13 is typified by early onset, mildly progressive cerebellar ataxia with accompanying dysarthria, mental retardation, and nystagmus. Symptoms and age of onset can vary slightly according to the causative mutation.