A small penis is what causes it?
(A) causes of morbidity
1. Gonadotropin secretion enough hypogonadism
(1) the organizational structure of the brain abnormalities: anencephaly in children with non-secretory function of the hypothalamic pituitary developed normally even if the absence of gonadotropin-releasing hormone testosterone resulted in congenital micropenis due to the small part of the brain pituitary agenesis of corpus callosum hypoplasia leading to the hypothalamus dysfunction, occipital encephalocele with cerebellar ataxia and other midline defects are a result of developmental abnormalities caused by lack of gonadotropin secretion in addition to the small penis lead to other systems with multiple malformations.
(2) no congenital abnormalities in brain tissue of gonadotropin-releasing hormone deficiency: causes for such a small penis, more common than the earlier ones for a variety of more specific causes of unclear, such as Kallmann syndrome, Prader-Willi Syndrome (Prader-Willi ) Lawrence-Moon-Beidel syndrome, often accompanied by multiple malformations, according to study and chromosome abnormalities are a result of endocrine metabolic and biochemical abnormalities caused by gonadotropin-releasing hormone such as luteinizing hormone deficiency.
2. Gonadotropin hypogonadism excessive secretion of these patients the secretory function of hypothalamic-pituitary were normal only in the testis during late pregnancy appears to reduce testosterone secretion Erzhi degeneration by means of negative feedback, excessive secretion of gonadotropin Erzhi The main reason caused by the small penis in the testis itself, such as congenital absence of testicular descent testicular failure, etc. Some of the patients with normal testicular luteinizing hormone receptor of its abnormal secretion as well as not enough testosterone also should pay attention to whether the gender anomaly.
3. Primary small penis In addition to these reasons, there are a small number of patients in the hypothalamus - pituitary - testicular axis hormone secretion and normal but there are a small penis can be deformed to the addition of growth in adolescence may be speculated that the cause was not clear late embryonic gonadotropin stimulation delayed a transient decline in testosterone secretion and other reasons a small number in some patients may have abnormal androgen receptor
Small penis sex chromosome abnormalities, such as patients can Klinefelter syndrome (47XXY) Multi-X syndrome (48XXXY and 49XXXXY) multi-chromosome (69XXY triploid) malformations.
(B) the pathogenesis of
Normal male penis development in the embryonic period of the first 12 weeks to complete three stages of the first sub-stage of a period of genital tubercle genital tubercle gradually extended similar to the 8 ~ 15mm long hill phase 2 for the penis a view to dihydrotestosterone (dihydrotestosteroneDHT ) under the action of the penis continues to grow cylindrical shape of about 16 ~ 38mm urethral groove extends to the glans penis, stage 3 the length of 38 ~ 45mm urethra fully developed.
Embryo development to the first 7 to 8 weeks gonads differentiate into testes gradually produced in the placenta chorionic gonadotropin (HCG) stimulated Leydig cells (Leydig's cells) produce testosterone after 4 months of pregnancy the fetus and promote secretion of hypothalamic gonadal hormone-releasing hormone (gonadotropin-nelasing hormoneGRH) to stimulate the anterior pituitary produces luteinizing hormone (LH) and urinary gonadotropin hormone (FSH) and FSH in the HCGLH common role of the continuous generation of testicular testosterone testosterone again in 5-α reductase under the action of DHT to stimulate the penis into a small penis because of the gradual growth of embryos after 14 weeks due to hormone deficiency.