Hypoplasia

Generality

Hypoplasia is the medical-histological term that describes an incomplete development of a tissue or organ, resulting from an insufficient or lower than normal number of cells.

Hypoplasia of the enamel

Hypoplasia is similar to aplasia but is less severe. Hence, a hypoplastic organ is more developed than an aplastic organ.
Among the organs and tissues that can be the subject of hypoplasia, we note: the testicles, the optic nerve, the ovaries, the heart, the tooth enamel, the thymus, the uterus, the corpus callosum, the cerebellum, the thumb, the pectoral muscles and the breasts.

Definition of hypoplasia

Hypoplasia is the term that, in the medical-histological field, indicates the underdevelopment or incomplete development of a tissue or organ, due to an insufficient or lower than normal number of cells.

HYPOPLASIA AND APLASIA: WHAT DIFFERENCE C "IS?

In medicine and histology, aplasia is the failure of an organ or tissue to develop; for "lack of development" s "means" development not completed ".
Hypoplasia is similar to aplasia but is less severe. This means that an organ or tissue affected by hypoplasia is more developed than an organ or tissue affected by aplasia.

ORIGIN OF THE NAME

The word "hypoplasia" derives from the "union of two terms of Greek origin, which are" hypo "(ὑπo) and" plasis "(πλάσις). The term" hypo "means" under "or" lower ", while the term" plasis ”means“ formation. ”Hence, the meaning of hypoplasia is“ sub-formation ”.

Types

There are various types of hypoplasia. Among the most well-known types of hypoplasia, they certainly deserve a mention:

• Hypoplasia of the testicles, in conditions such as male hypogonadism, Klinefelter's syndrome, varicocele, orchitis etc .;
• The hypoplasia of the optic nerve;
• Enamel hypoplasia, also called Turner's tooth;
• The two cardiac hypoplasia, known as hypoplastic left heart syndrome and hypoplastic right heart syndrome;
• Hypoplasia of the thymus in DiGeorge syndrome;
• L "uterine hypoplasia;
• The hypoplasia of the corpus callosum;
• Hypoplasia of the depressor muscle of the corner of the mouth. To learn more about the depressor muscle of the corner of the mouth, readers can consult the article here;
• Unilateral hypoplasia of the pectoral muscles in a condition known as Poland's syndrome;
• Ovarian hypoplasia, also known as ovarian hypoplasia;
• Hypoplasia of the nails, in conditions such as Turner syndrome;
• Breast hypoplasia, also known as breast hypoplasia;
• Cerebellar hypoplasia, ie hypoplasia of the cerebellum;
• Thumb hypoplasia, also called congenital thumb hypoplasia;
• Mandibular hypoplasia, in Goldenhar's syndrome;
• Pulmonary hypoplasia, that is, hypoplasia of the lungs.

Below, the article briefly describes the causes and consequences of some of the aforementioned types of hypoplasia.

HYPOPLASIA OF TESTICLES

Also known as testicular hypotrophy or simply small testicles, testicular hypoplasia is potentially responsible for: reduced spermatogenesis, resulting in a decrease in fertility, and a decrease in the production of steroid hormones, with consequent failure or incomplete development of secondary sexual characteristics (eg : pubic hair, beard, etc.).

HYPOPLASIA OF THE OPTICAL NERVE

The optic nerve is a collection of nerve fibers, having the important task of transmitting visual signals from the organs of vision - the eyes - to the brain, for the processing of vision.
Identified with the Roman number 2 (II), the optic nerve represents one of the twelve pairs of cranial nerves.
Generally, people with optic nerve hypoplasia complain of: more or less marked visual difficulties affecting one or both eyes, mono- or bilateral nystagmus and a certain degree of strabismus.
In some circumstances, the hypoplasia of the optic nerve is associated with some particular malformations of the central nervous system, on which the presence of seizures and developmental delay may depend.

HYPOPLASIA OF THE ENAMEL

Enamel hypoplasia is an anomaly of the teeth, in the presence of which the dental enamel, while presenting normal hardness, is extremely thin, scarce in quantity and, at times, covered with holes, which expose the dentin.
At the base of the "hypoplasia of the enamel, c" is an incorrect process of formation of the so-called enamel matrix (or enamel matrix).
Causes of enamel hypoplasia include: nutritional deficiencies, celiac disease, congenital syphilis, hypocalcemia, premature birth, trauma to the deciduous dentition and fluorosis.

HYPOPLASIC LEFT HEART SYNDROME

The heart of the human being can ideally be divided into two halves: a right half and a left half.
Composed of a right atrium and a right ventricle, the right half of the heart has the task of sending to the lungs, for its oxygenation, oxygen-poor blood, received from the organs and tissues of the body.
Consisting of the left atrium and left ventricle, however, the left half of the heart has the task of pumping oxygenated blood to the organs and tissues of the body, returning from the lungs.
Hypoplastic left heart syndrome is a rare congenital heart malformation characterized by underdevelopment of the left half of the heart (and its valves).
Its presence involves various difficulties in blood circulation, both as regards the passage of blood from the left atrium to the left ventricle and as regards the passage from the left ventricle to the aorta.
The symptom picture of hypoplastic left heart syndrome is found from birth and usually consists of: cyanosis, breathing difficulties, cold hands and feet, drowsiness and shock.

HYPOPLASIC RIGHT HEART SYNDROME

Hypoplastic right heart syndrome is another rare congenital heart malformation characterized by incomplete development of the right atrium and right ventricle (and their valves).
Its presence causes a reduced blood flow to the lungs, resulting in poor blood oxygenation. Due to poor blood oxygenation, the patient experiences cyanosis in various parts of the body, including: skin, lips and fingertips.

UTERINE HYPOPLASIA

Uterine hypoplasia is a congenital malformation, which involves the presence of a small uterus.
Being part of the so-called anomalies of the Müllerian ducts (such as uterine agenesis or Müllerian agenesis), uterine hypoplasia is responsible for: primary amenorrhea, poor opening of the vagina and infertility.

CEREBELLAR HYPOPLASIA

Cerebellar hypoplasia represents a heterogeneous group of cerebellar malformations, all of which involve a very similar symptom picture, including: early onset non-progressive ataxia, hypotonia and motor learning impairment.
Possible causes of cerebellar hypoplasia include: hereditary factors, severe metabolic abnormalities, viral agents and / or toxic agents.

CONGENITAL HYPOPLASIA OF THE THUMB

Congenital hypoplasia of the thumb is an anomaly present from birth, which is characterized by a more or less evident underdevelopment of the thumb of one or both hands.
A typical sign of conditions such as Holt-Oram syndrome, VATER syndrome, TAR syndrome and Fanconi anemia, thumb hypoplasia affects one in every 100,000 newborns.