Signs and symptoms of this disorder include weak muscle tone (hypotonia), sagging facial features, seizures, intellectual disability, and developmental delay. The patients have brittle hair and metaphyseal widening. In rare cases, symptoms begin later in childhood and are less severe. Affected infants may be born prematurely. Symptoms appear during infancy and are largely a result of abnormal intestinal copper absorption with a secondary deficiency in copper-dependent mitochondrial enzymes. Normal or slightly slowed development may proceed for 2 to 3 months, and then there will be severe developmental delay and a loss of early developmental skills. Menkes Disease is also characterized by seizures, failure to thrive, subnormal body temperature, and strikingly peculiar hair, which is kinky, colorless or steel-colored, and easily broken. There can be extensive neurodegeneration in the gray matter of the brain. Arteries in the brain can also be twisted with frayed and split inner walls. This can lead to rupture or blockage of the arteries. Weakened bones (osteoporosis) may result in fractures.

Occipital horn syndrome (sometimes called X-linked cutis laxa or Ehlers-Danlos type 9) is a mild form of Menkes syndrome that begins in early to middle childhood. It is characterized by calcium deposits in a bone at the base of the skull (occipital bone), coarse hair, loose skin, and joints.

Other lipid storage disorders that are generally not classified as sphingolipidoses include fucosidosis, Schindler disease and Wolman disease.

A lipid storage disorder (or lipidosis) can be any one of a group of inherited metabolic disorders in which harmful amounts of fats or lipids accumulate in some of the body’s cells and tissues. People with these disorders either do not produce enough of one of the enzymes needed to metabolize and break down lipids or they produce enzymes that do not work properly. Over time, this excessive storage of fats can cause permanent cellular and tissue damage, particularly in the brain, peripheral nervous system, liver, spleen and bone marrow.

Inside cells under normal conditions, lysosomes convert, or metabolize, lipids and proteins into smaller components to provide energy for the body.

Theoretically, a mutation in any of the may cause disease, but below are some notable ones, with short description of symptoms:

- Adrenoleukodystrophy; leads to progressive brain damage, failure of the adrenal glands and eventually death.

- Alport syndrome; glomerulonephritis, endstage kidney disease, and hearing loss.

- Androgen insensitivity syndrome; variable degrees of undervirilization and/or infertility in XY persons of either gender

- Barth syndrome; metabolism distortion, delayed motor skills, stamina deficiency, hypotonia, chronic fatigue, delayed growth, cardiomyopathy, and compromised immune system.

- Blue cone monochromacy; low vision acuity, color blindness, photophobia, infantile nystagmus.

- Centronuclear myopathy; where cell nuclei are abnormally located in skeletal muscle cells. In CNM the nuclei are located at a position in the center of the cell, instead of their normal location at the periphery.

- Charcot–Marie–Tooth disease (CMTX2-3); disorder of nerves (neuropathy) that is characterized by loss of muscle tissue and touch sensation, predominantly in the feet and legs but also in the hands and arms in the advanced stages of disease.

- Coffin–Lowry syndrome; severe mental retardation sometimes associated with abnormalities of growth, cardiac abnormalities, kyphoscoliosis as well as auditory and visual abnormalities.

- Fabry disease; A lysosomal storage disease causing anhidrosis, fatigue, angiokeratomas, burning extremity pain and ocular involvement.

- Hunter's Syndrome; potentially causing hearing loss, thickening of the heart valves leading to a decline in cardiac function, obstructive airway disease, sleep apnea, and enlargement of the liver and spleen.

- Hypohidrotic ectodermal dysplasia, presenting with hypohidrosis, hypotrichosis, hypodontia

- Kabuki syndrome; multiple congenital anomalies and mental retardation.

- Spinal and bulbar muscular atrophy; muscle cramps and progressive weakness

- Lesch-Nyhan syndrome; neurologic dysfunction, cognitive and behavioral disturbances including self-mutilation, and uric acid overproduction (hyperuricemia)

- Lowe Syndrome; hydrophthalmia, cataracts, intellectual disabilities, aminoaciduria, reduced renal ammonia production and vitamin D-resistant rickets

- Menkes disease; sparse and coarse hair, growth failure, and deterioration of the nervous system

- Nasodigitoacoustic syndrome; mishaped nose, brachydactyly of the distal phalanges, sensorineural deafness

- Nonsyndromic deafness; hearing loss

- Norrie disease; cataracts, leukocoria along with other developmental issues in the eye

- Occipital horn syndrome; deformations in the skeleton

- Ocular albinism; lack of pigmentation in the eye

- Ornithine transcarbamylase deficiency; developmental delay and mental retardation. Progressive liver damage, skin lesions, and brittle hair may also be seen

- Siderius X-linked mental retardation syndrome; cleft lip and palate with mental retardation and facial dysmorphism, caused by mutations in the histone demethylase PHF8

- Simpson-Golabi-Behmel syndrome; coarse faces with protruding jaw and tongue, widened nasal bridge, and upturned nasal tip

- Spinal muscular atrophy caused by UBE1 gene mutation; weakness due to loss of the motor neurons of the spinal cord and brainstem

- Wiskott-Aldrich syndrome; eczema, thrombocytopenia, immune deficiency, and bloody diarrhea

- X-linked Severe Combined Immunodeficiency (SCID); infections, usually causing death in the first years of life

- X-linked sideroblastic anemia; skin paleness, fatigue, dizziness and enlarged spleen and liver.

Menkes disease (MNK), also known as Menkes syndrome, is an X-linked recessive disorder that affects copper levels in the body, leading to copper deficiency.

It is more common in males than females, because it only takes one copy of the X-linked recessive gene to be expressed for a male to develop the disease. In order for females to develop the disorder they would need to express two copies of the gene, one on each X chromosome to develop the disorder. MNK is characterized by kinky hair, growth failure, and deterioration of the nervous system. It is caused by mutations in the copper transport gene, ATP7A, which is responsible for making a protein that is important for regulating the copper levels in the body.

The onset of Menkes disease typically begins during infancy, affecting about 1 in 100,000 to 250,000 newborns. Infants with MNK syndrome often do not live past the age of 3. The disorder was first described by John Hans Menkes in 1962.

It is characterized by a deficiency in biliary copper excretion that causes deformations in the skeleton. These include projections on the back of the skull (parasagittal bone exostoses arising from the occipital bone—the so-called "occipital horns") as well as deformities of the elbow, radial head dislocation, hammer-shaped lateral ends of the clavicles, and abnormalities of the hips and pelvis.

OHS presents in early to middle childhood. Children may present with features such as:

The signs and symptoms in glycogen storage disease type IX include:

- Enlarged liver

- Slowed growth

- Motor development delay (mild)

- Low blood sugar accompanied by ketosis

- Lack of muscle tone

Most of these signs and symptoms diminish as adulthood sets in.

A genetic disorder is a genetic problem caused by one or more abnormalities in the genome, especially a condition that is present from birth (congenital). Most genetic disorders are quite rare and affect one person in every several thousands or millions.

Genetic disorders may be hereditary, passed down from the parents' genes. In other genetic disorders, defects may be caused by new mutations or changes to the DNA. In such cases, the defect will only be passed down if it occurs in the germ line. The same disease, such as some forms of cancer, may be caused by an inherited genetic condition in some people, by new mutations in other people, and mainly by environmental causes in other people. Whether, when and to what extent a person with the genetic defect or abnormality will actually suffer from the disease is almost always affected by the environmental factors and events in the person's development.

Some types of recessive gene disorders confer an advantage in certain environments when only one copy of the gene is present.

OHS is a milder allelic variant of Menkes disease, having a later age of onset and being associated with far less severe central neurodegeneration. The milder nature of OHS is often attributable to ‘leaky’ splice junction mutations that allow 20–30% of ATP7A messenger RNA (mRNA) transcripts to be correctly processed. As in cases of Menkes disease, individuals with OHS manifest connective tissue abnormalities resulting from deficient activity of lysyl oxidase, a copper-requiring enzyme that normally deaminates lysine and hydroxylysine in the first step of collagen crosslink formation. Such individuals also often endure inconvenient dysautonomic signs and symptoms related to a partial deficiency in dopamine-β-hydroxylase (DBH) activity. DBH, another copper-dependent enzyme, normally converts dopamine to norepinephrine, a crucial neurotransmitter in norepinephrinergic neurons. A natural mouse model of OHS, the so-called mottled blotchy model, recapitulates the connective tissue abnormalities, DBH deficiency and mild CNS damage seen in humans.

Sphingolipidoses (singular "sphingolipidosis") are a class of lipid storage disorders relating to sphingolipid metabolism. The main members of this group are Niemann–Pick disease, Fabry disease, Krabbe disease, Gaucher disease, Tay–Sachs disease and metachromatic leukodystrophy. They are generally inherited in an autosomal recessive fashion, but notably Fabry disease is X-linked recessive. Taken together, sphingolipidoses have an incidence of approximately 1 in 10,000, but substantially more in certain populations such as Ashkenazi Jews. Enzyme replacement therapy is available to treat mainly Fabry disease and Gaucher disease, and people with these types of sphingolipidoses may live well into adulthood. The other types are generally fatal by age 1 to 5 years for infantile forms, but progression may be mild for juvenile- or adult-onset forms.

Some specific symptoms vary from one type of leukodystrophy to the next but the vast majority of symptoms are shared as the causes for the disease generally have the same effects. Symptoms are dependent on the age of onset, which is predominantly in infancy and early childhood, although the exact time of onset may be difficult to determine. Hyperirritability and hypersensitivity to the environment are common, as well as some tell-tale physical signs including muscle rigidity and a backwards-bent head. Botox therapy is often used to treat patients with spasticity. Juvenile and adult onsets display similar symptoms including a decrease or loss in hearing and vision. While children do experience optic and auditory degeneration, the course of the disease is usually too rapid, causing death relatively quickly, whereas adults may live with these conditions for many years. In children, spastic activity often precedes progressive ataxia and rapid cognitive deterioration which has been described as mental retardation. Epilepsy is commonplace for patients of all ages. More progressed patients show weakness in deglutition, leading to spastic coughing fits due to inhaled saliva. Classic symptomatic progression of juvenile x-linked adrenoleukodystrophy is shown in the 1992 film, "Lorenzo's Oil".

Course and timetable are dependent on the age of onset with infants showing a lifespan of 2–8 years, juveniles 2–10 years and adults typically 10+ years. Adults typically see an extended period of stability followed by a decline to a vegetative state and death. While treatments do exist, most are in the experimental phase and can only promise a halt in the progression of symptoms, although some gene therapies have shown some symptomatic improvement. The debilitating course of the disease has led to numerous philosophical and ethical arguments over experimental clinical trials, patients’ rights and physician-assisted suicide.

The most common X-linked recessive disorders are:

- Red-green color blindness, a very common trait in humans and frequently used to explain X-linked disorders. Between seven and ten percent of men and 0.49% to 1% of women are affected. Its commonness may be explained by its relatively benign nature. It is also known as daltonism.

- Hemophilia A, a blood clotting disorder caused by a mutation of the Factor VIII gene and leading to a deficiency of Factor VIII. It was once thought to be the "royal disease" found in the descendants of Queen Victoria. This is now known to have been Hemophilia B (see below).

- Hemophilia B, also known as Christmas Disease, a blood clotting disorder caused by a mutation of the Factor IX gene and leading to a deficiency of Factor IX. It is rarer than hemophilia A. As noted above, it was common among the descendants of Queen Victoria.

- Duchenne muscular dystrophy, which is associated with mutations in the dystrophin gene. It is characterized by rapid progression of muscle degeneration, eventually leading to loss of skeletal muscle control, respiratory failure, and death.

- Becker's muscular dystrophy, a milder form of Duchenne, which causes slowly progressive muscle weakness of the legs and pelvis.

- X-linked ichthyosis, a form of ichthyosis caused by a hereditary deficiency of the steroid sulfatase (STS) enzyme. It is fairly rare, affecting one in 2,000 to one in 6,000 males.

- X-linked agammaglobulinemia (XLA), which affects the body's ability to fight infection. XLA patients do not generate mature B cells. B cells are part of the immune system and normally manufacture antibodies (also called immunoglobulins) which defends the body from infections (the humoral response). Patients with untreated XLA are prone to develop serious and even fatal infections.

- Glucose-6-phosphate dehydrogenase deficiency, which causes nonimmune hemolytic anemia in response to a number of causes, most commonly infection or exposure to certain medications, chemicals, or foods. Commonly known as "favism", as it can be triggered by chemicals existing naturally in broad (or fava) beans.

Glycerol Kinase Deficiency (GKD) is an X-linked recessive enzyme defect that is heterozygous in nature. Three clinically distinct forms of this deficiency have been proposed, namely infantile, juvenile, and adult. National Institutes of Health and its Office of Rare Diseases Research (ORDR) branch classifies GKD as a rare disease, known to affect fewer than 200,000 individuals in the United States. The responsible gene lies in a region containing genes in which deletions can cause Duchenne muscular dystrophy and adrenal hypoplasia congenita. Combinations of these three genetic defects including GKD are addressed medically as Complex GKD.

The signs and symptoms of X-linked recessive hypoparathyroidism are characteristic of hypoparathyroidism and its consequent hypocalcemia. They include acute symptoms, like paresthesia, twitching of the hands and feet, unconsciousness, and trouble breathing; and chronic symptoms, including seizures, tiredness, irritability, cardiac insufficiency, abnormal heart rhythms, papilledema, cataracts, calcium deposits in the brain, and loss or brittleness of hair, skin, and nails.

The currently recognized features of HHS are cerebellar hypoplasia, immunodeficiency, progressive bone marrow failure, and intrauterine growth retardation. HHS patients also commonly exhibit symptoms such as microcephaly, aplastic anemia, and mental retardation.

Chondrodysplasia punctata is a clinically and genetically diverse group of rare diseases, first described by Erich Conradi (1882–1968), that share the features of stippled epiphyses and skeletal changes.

Types include:

- Rhizomelic chondrodysplasia punctata , ,

- X-linked recessive chondrodysplasia punctata

- Conradi-Hünermann syndrome

- Autosomal dominant chondrodysplasia punctata

X-linked recessive chondrodysplasia punctata is a type of chondrodysplasia punctata that can involve the skin, hair, and cause short stature with skeletal abnormalities, cataracts, and deafness.

This condition is also known as arylsulfatase E deficiency, CDPX1, and X-linked recessive chondrodysplasia punctata 1. The syndrome rarely affects females, but they can be carriers of the recessive allele. Although the exact number of people diagnosed with CDPX1 is unknown, it was estimated that 1 in 500,000 have CDPX1 in varying severity. This condition is not linked to a specific ethnicity. The mutation that leads to a deficiency in arylsulfatase E. (ARSE) occurs in the coding region of the gene.Absence of stippling, deposits of calcium, of bones and cartilage, shown on x-ray, does not rule out chondrodysplasia punctata or a normal chondrodysplasia punctata 1 (CDPX1) gene without mutation. Stippling of the bones and cartilage is rarely seen after childhood. Phalangeal abnormalities are important clinical features to look for once the stippling is no longer visible. Other, more severe, clinical features include respiratory abnormalities, hearing loss, cervical spine abnormalities, delayed cognitive development, ophthalmologic abnormalities, cardiac abnormalities, gastroesophageal reflux, and feeding difficulties. CDPX1 actually has a spectrum of severity; different mutations within the CDPX1 gene have different effects on the catalytic activity of the ARSE protein. The mutations vary between missense, nonsense, insertions, and deletions.

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.

In addition to HHS-specific sequelae, HHS patients frequently present with the mucocutaneous triad of nail dysplasia, lacy skin pigmentation, and oral leukoplakia

Severe cases of CLA manifest in the neonatal period; milder cases caused by mtDNA mutations may not manifest until as late as early adulthood. Symptoms may be constant or brought on by an event causing stress, such as an asthma attack, seizure, or infection. Symptoms in the neonatal period include hypotonia, lethargy, vomiting, and tachypnea. As the disease progresses, it causes developmental delay, cognitive disabilities, abnormal development of the face and head, and organ failure.

The incidence of this disease is not precisely known but it is considered to be rare (< 1/10 population). It has been reported in 15 families to date mostly from Canada, Finland and France.

This disease usually presents between the ages of 5 to 10 years old. The usual picture is with weakness involving the upper legs and affects activities such as running and climbing stairs. As the condition progresses, patients tend to experience weakness in their lower legs and arms. Some remain able to walk in advanced age, while others require assistance in adulthood.

Glycogen storage disease type IX is a hereditary deficiency of glycogen phosphorylase kinase B that affects the liver and skeletal muscle tissue. It is inherited in an X-linked or autosomal recessive manner.

This condition occurs almost exclusively in males. The mutation may be spontaneous or inherited from the mother. The typical clinical features are:

- flat nasal tip

- short columella

- maxillary hypoplasia

- involvement of terminal phalanges

- stippled chondrodystrophy

Most children with Allan–Herndon–Dudley syndrome have weak muscle tone (hypotonia) and underdevelopment of many muscles (muscle hypoplasia). As they get older, they usually develop joint deformities called contractures, which restrict the movement of certain joints. Abnormal muscle stiffness (spasticity), muscle weakness, and involuntary movements of the arms and legs also limit mobility. As a result, many people with Allan–Herndon–Dudley syndrome are unable to walk independently and become wheelchair-bound by adulthood.

Glycerol Kinase Deficiency causes the condition known as hyperglycerolemia, an accumulation of glycerol in the blood and urine. This excess of glycerol in bodily fluids can lead to many more potentially dangerous symptoms. Common symptoms include vomiting and lethargy. These tend to be the only symptoms, if any, present in adult GKD which has been found to present with fewer symptoms than infant or juvenile GKD. When GKD is accompanied by Duchenne Muscular Dystrophy and Adrenal Hypoplasia Congenita, also caused by mutations on the Xp21 chromosome, the symptoms can become much more severe. Symptoms visible at or shortly after birth include:

- cryptorchidism

- strabismus

- seizures

Some other symptoms that become more noticeable with time would be:

- metabolic acidosis

- hypoglycemia

- adrenal cortex insufficiency

- learning disabilities

- osteoporosis

- myopathy

Many of the physically visible symptoms, such as cryptorchidism, strabismus, learning disabilities, and myopathy, tend to have an added psychological effect on the subject due to the fact that they can set him or her apart from those without GKD. Cryptorchidism, the failure of one or both of the testes to descend to the scrotum, has been known to lead to sexual identity confusion amongst young boys because it is such a major physiological anomaly. Strabismus is the misalignment of one’s eyes. Typically, one is focused but the other is “lazy” and is directed inward or out ward (up and down is less common but does occur).