Albinism is caused byGene mutationCongenital single gene genetic disease caused bymelaninOr melanosome biosynthesis defect, mainly manifested as hypopigmentation or loss of skin, eyes or hair.The common types are ocular skin albinism (OCA) and ocular albinism (OA).Standard genetic patterns includeAutosomal recessive inheritanceandX-linked recessive inheritance。The global prevalence rate of albinism is about 1:17000, that is, one person in every 17000 people suffers from albinism on average.Close relative marriage and childbearing will increase the prevalence rate.
All types of albinism can produce eye symptoms, such asHypopigmentation、Nystagmus、PhotophobiaAnd decreased vision.The skin and hair of patients with oculocutaneous albinism will lack melaninultraviolet raysSensitive, easy to sunburn, and even induce skin cancer.Patients with syndrome type albinism may have other organ or system abnormalities.
Albinism cannot be completely recovered through treatment at present, and only symptomatic treatment can be carried out to alleviate symptoms and pain.Patients need to have regular eye examinations and avoid prolonged exposure to the sun.Eye problems such as nystagmus and visual impairment need surgical correction.Patients with syndrome type albinism may need more comprehensive hematological examination, includingroutine blood test、Coagulation functionandT cell、NK cellsQuantity, etc.
TCM disease name
Albinism
Foreign name
albinism
Visiting department
Dermatology, ophthalmology
Multiple population
No specific population, affected by genetic factors
Common causes
Abnormal melanogenesis, congenital gene mutation
common symptom
Eye hypopigmentation, nystagmus, photophobia, low vision, sensitivity to ultraviolet rays, skin and hair hypopigmentation or loss
According to different clinical manifestations and involved genes, albinism can be divided into two major categories: non syndromic type and syndromic type.At present, 18 albinism subtypes and their pathogenic genes have been identified.
Nonsyndromic albinism
Non syndromic albinism, also known as "simple albinism", is only manifested in eyes, skin, hair and other partspigmentImpairment and visual impairment, including ocular skin albinism and ocular albinism.
Oculocutaneous albinism (OCA): formerly known as "generalized albinism".The pigmentation of the whole body skin, hair and eye skin is reduced or lacking, including ocular skin albinism type 1~7 (OCA-1~7), which is the most common type of albinism in the world and is inherited in autosomal recessive mode.
Ocular albinism (OA): Previously known as "partial albinism", only ocular pigment deficiency and normal skin and hair pigment.It includes X-linked recessive albinism type 1 (OA1) and autosomal recessive albinism type (AROA).OA1 is the most common type of ocular albinism.
Syndrome type albinism
The patient even shows whitening of eyes or eye skin, and is often accompanied by complications of other organs or systems, such aspulmonary fibrosis，myocarditis，Inflammatory enteropathyEtc.Some may die due to serious complications, which were previously called Hermansky Pudlak syndrome type 1-10 (HPS-1-10) and Chediak Higashi syndrome type 1 (CHS-1).
Hermansky Pudlak syndrome (HPS): in addition to OCA or OA manifestations, it is often accompanied by bleeding tendency and brain, lung, kidney and other organ damage caused by wax like substance deposition in tissues.Wax deposition can lead to pulmonary fibrosis or cardiomyopathy, which is the main cause of death in middle-aged patients.Some patients also have inflammatory bowel disease (such as HPS-1 subtypes) or immune deficiency (such as HPS-2 and HPS-10 subtypes).
Chediak Higashi syndrome (CHS): clinical features include OCA symptoms, swelling of perinuclear lysosomes, progressive nervous system damage or hemophagocytic lymphohistiocytosis.At the same time, patients with congenital immune deficiency are prone to infection and tumor.
pathogeny
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The occurrence of albinism is due to the abnormal production of melanin.The type and amount of melanin produced by the human body determines the color of skin, hair and eyes.The production of pigment in the body involves many links, which is a complex and delicate regulation process. Any link defect may lead to the production of pigment obstacles, leading to albinism or other hypopigmentation diseases.
Oculocutaneous albinism (OCA)
belong toAutosomal recessive inheritance。Both parents of albinism patients carry the disease causing gene of albinism, and the carriers themselves do not suffer from disease, but they can pass the disease causing gene to their children.Children who inherit disease causing genes from both parents will get sick, and men and women have equal opportunities to get sick. The probability of this situation is 1/4.
Ocular Albinism (OA)
OA1 belongs toX-linked recessive inheritance。If the father has no disease gene, the mother carries the disease gene on the X chromosome, which can be passed on to her children. The son has a half chance of getting sick, and the daughter is a carrier or has no disease gene.If the father is sick but the mother has no disease gene, the father can only pass on the X chromosome with the disease gene to the daughter, so the son is normal and the daughter is the carrier.Therefore, OA1 almost only occurs in men.It accounts for a relatively small proportion in all types of albinism.
The autosomal recessive albinism (AROA) belongs to autosomal recessive inheritance, and its inheritance mode is the same as that of ocular skin albinism (OCA).
symptom
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All types of albinism can lead to different degrees of eye symptoms: hypopigmentation, nystagmus, photophobia, low vision, etc.Oculocutaneous albinism (OCA) patients also show a reduction or lack of melanin in hair and skin, sensitivity to ultraviolet light, and are prone to sunburn, and even induceSkin cancer。In patients with syndrome type albinism, in addition to albinism, other organ or system abnormalities may also occur.
Typical symptoms
The typical clinical characteristics of different types of albinism are different.
Skin color
The skin color of patients with ocular skin albinism (OCA) is mostly white or pink.The skin color of patients with ocular albinism (OA) is normal.
The skin of albino patients with complete lack of pigment is white for life.Patients with partial lack of pigment will produce some pigment with age, and the skin color will be slightly deepened.
Some patients may have the following symptoms when exposed to the sun:
Freckle;
Nevus with or without pigment;Nevus without pigment is usually pink;
Sunburn, large freckle like spots;
Easily sunburned, but not tanned.
Hair Color
Due to the different degree of pigment deficiency, the hair color of albino patients also varies greatly, from white, yellow, brown, red to black.In patients with amelanotic albinism, the hair color is white for life.With pigmented patients, the hair color will deepen with age.In patients with albinism, the hair color is normal.
Eye color
Achromatic patientsiris(The colored part of the eye) is pink, translucent, and the pupil is red.The iris color of pigmented patients varies from light blue to dark brown. With age, the iris color will deepen and the vision will improve.
Other eye problems
Visual impairment is an important feature of all types of albinism.Eye lesions include:
Nystagmus: involuntary, rhythmic and conjugate nystagmus of the eyeball;
Photophobia: due to the lack of pigment in the fundus of the eye, it cannot tolerate the stimulation of daily light;
Strabismus: two eyes cannot focus on the same target at the same time;
Compensatory head position: in order to alleviate the discomfort caused by nystagmus and strabismus, patients are accustomed to the special posture formed by tilting their heads to gaze;
Macular dysplasia: The macula is responsible for vision and color vision.Macular dysplasia can lead to poor vision.Ocular coherence tomography (OCT) showed flattening or disappearance;
Poor vision: high myopia or hyperopia, low vision, severe vision can be limited.
Accompanying symptoms
Syndrome type albinism can cause serious complications such as chronic inflammation or fibrosis due to the involvement of other organs and systems such as lungs, hearts and intestines, or recurrent infection due to the impairment of immune function, even endangering life.
Medical treatment
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The main harm of albinism is eye damage and skin cancer. Therefore, when there are eye problems, skin and hair with light color, you should go to the dermatology and ophthalmology department in time to get medical advice.
Indication for medical treatment
The baby's skin and hair are light or lacking in color at birth;
Light eyes, accompanied by photophobia, nystagmus, strabismus, low vision and other eye symptoms;
The skin is prone to ecchymosis or frequent nosebleed, and bleeding continues during tooth extraction or surgery;
Susceptibility to chronic infectious diseases.It is necessary to seek medical advice in time to determine whether there is more serious syndrome type albinism such as HPS or CHS.
Diagnostic process
First, the doctor may ask the following questions to understand the medical history:
Whether there is a history of close relatives' marriage and childbearing and a family history of albinism;
Whether there is hypopigmentation of eyes or eyes, skin and hair at birth;
Whether there are eye symptoms such as nystagmus, photophobia, strabismus, and poor eyesight;
Whether it is easy to get sunburn, but not easy to get sunburn;
Whether there are often skin ecchymosis, easy bleeding, long bleeding time, etc;
Whether they are susceptible to chronic infectious diseases.
Secondly, check the pigmentation of hair, skin and eyes;
Then you should go to the ophthalmology department to check whether there is nystagmus, strabismus, visual impairment, etc., and whether there is albinism fundus change;
Finally, through genetic examination, that is, gene testing, to determine whether it is albinism and the type of albinism.
Visiting department
The first department is dermatology, followed by ophthalmology.
Relevant inspection
physical examination
Check the patient's hair and skin pigmentation, and make a preliminary diagnosis of albinism.
Ophthalmic examination
In addition to visual observation of iris color, nystagmus and visual acuity, ophthalmic examination often requires the help of some specialized equipment, such as eyeground mirror, optical coherence tomography (OCT), nystagmus meter, eye electrophysiological instrument, etc., to evaluate potential nystagmus, strabismus and photosensitivity.
Genetic examination
Through gene testing and genetic analysis, the type and genetic mode of albinism can be determined.
Hematology examination
The diagnosis of syndrome type albinism often requires more comprehensive hematological examination, including routine blood test, coagulation function, T cell, NK cell and other immunological tests.Panoramic observation of platelet dense particles under electron microscope is the gold standard for diagnosis of HPS and CHS.
Skin pathology
Under special circumstances, skin pathology is needed to detect the skinMelanocyteAnd whether the morphology of melanosomes is abnormal.
other
For adult HPS patients, it is usually necessary to make a comprehensive assessment of the function of other organs, such as the changes of lung, heart and brain with high-resolution CT, and whether there is inflammatory bowel disease with colonoscopy.High performance liquid chromatography can accurately quantify the pigment content of skin or hair.
differential diagnosis
Vitiligo
An acquired hypopigmentation disease, the cause of which is still unknown, and the "immunology theory" is currently considered to beVitiligoMain causes of occurrence.Genetic factors also play a role in the pathogenesis of vitiligo.Leukoplakia can occur at any age, at any location, and can be localized and generalized, and can develop and expand progressively.Sometimes generalized vitiligo can affect the whole body, and the hair on the white spot also turns white, but other organs and systems are not affected.
Also known as "pattern leukoplakia", it is autosomal dominant inheritance.The patient has depigmentation spots at birth, which can occur in any part of the body, but are common in the center of the face, chest, abdomen and other front sides of the body.There may be an island like hyperpigmentation area in the center of the leukoplakia.The most characteristic is the triangular or rhombic white spot in the middle or slightly off the forehead, accompanied by localized white hair across the hairline.Sometimes white hair on the forehead is the only manifestation of the disease.Some patients may also have other developmental abnormalities.
An amino acid metabolic disease with autosomal recessive inheritance.It can be manifested as hypopigmentation of skin and hair.Its main clinical features are stunting, mental retardation, psychiatric symptoms, dry skin, sweat and urine with special smell of rats.Early diagnosis, active treatment and good prognosis.
treatment
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At present, there is no effective treatment for albinism, which can not be cured and is limited to symptomatic treatment.
Acute treatment
The patients with Hermansky Pudlak syndrome (HPS) in acute stage can be treated by blood transfusion.Patients with severe pulmonary fibrosis may consider lung transplantation.Inflammatory bowel disease can be treated with hormone drugs or other anti-inflammatory drugs.
When patients with Chediak Higashi syndrome (CHS) have severe immune deficiency, bone marrow transplantation should be considered.
General treatment
Daily protection
Due to the lack of pigment in the skin and eyes of albino patients and their lack of normal protection against ultraviolet rays, their risk of sunburn and skin cancer increases. Therefore, long-term exposure to the sun should be avoided to minimize the damage of ultraviolet rays to the eyes and skin.When the ultraviolet ray is strong, you should try to avoid going out, or wear long sleeved clothes, hats, sunglasses, and sunscreen products with high sun protection factor (SPF).
Patients with syndrome type albinism should avoid taking drugs containing acetylsalicylic acid and aspirin because they have bleeding tendency;During delivery, tooth extraction or major surgery, the doctor shall be informed of the condition and corresponding preventive measures shall be taken in advance.
Ophthalmic monitoring and correction
Patients need to have eye examinations regularly to monitor their vision.asmyopia、hyperopiaorastigmatismFor those who have problems, they can wear glasses to improve.Those with severe head strabismus and nystagmus can be corrected by surgery to improve appearance and gaze quality, but the improvement of vision is limited.
psychological counseling
Due to special appearance and eye disability, patients are prone to psychological problems such as inferiority complex, and there are different degrees of obstacles in learning, work, marriage and childbearing, so they can seek the help of a psychologist.
surgical treatment
The disease generally does not require surgical treatment.
TCM treatment
The TCM treatment of the disease is not supported by evidence-based medical evidence, but some TCM treatment methods or drugs can alleviate symptoms, so it is recommended to go to regular medical institutions and treat under the guidance of doctors.
Frontier treatment
The treatment guidelines for Hermansky Pudlak syndrome (HPS) issued in 2013 pointed out that "preoperative useDesmopressin(Desmopressin Acetate Ampules, DDAVP) administered intravenously, can be stimulated byVon Willebrand factorThe release of vWF (von Willebrand Factor, vWF) can prevent and alleviate the bleeding tendency of HPS ".However, the research of Chinese scholars suggests that HPS-1, HPS-3 and HPS-6 subtypes are the main types of HPS in China. These subtypes lack the effect of effectively releasing vWF in the preoperative treatment of DDAVP, and other hemostasis schemes need to be considered.
prognosis
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Albinism is a congenital hereditary disease and cannot be cured.The patient's skin is prone to sunburn and skin cancer due to the lack of protection from melanin.
Daily protection can reduce the occurrence of skin damage.Except for a few severe syndrome type albinism, the life span of most albinism patients is normal.
complication
Ocular complications
Albinism patients may have vision problems of varying degrees, affecting life, learning, employment and driving ability.
Skin complications
The skin of albino patients is very sensitive to light, easy to get sunburn and skin cancer.
Psycho psychological problems
Albinism patients may suffer discrimination due to their different appearance from ordinary people. In addition, eye disability may lead to inferiority complex and affect social interaction.
Other complications
Syndrome type albinism may have bleeding tendency, chronic inflammation or pulmonary fibrosis and other complications, even life-threatening in serious cases.
