Disease relevance of Hypopigmentation

• Because patients with the Prader-Willi syndrome may also have hypopigmentation and strabismus, we wondered whether they too might have misrouting of optic fibers [1].
• Hermansky-Pudlak syndrome type 3 in Ashkenazi Jews and other non-Puerto Rican patients with hypopigmentation and platelet storage-pool deficiency [2].
• Ocular albinism type 1 (OA1) is an inherited disorder characterized by severe reduction of visual acuity, photophobia, and retinal hypopigmentation [3].
• Mutations in MITF (microphthalmia transcription factor) cause Waardenburg syndrome type 2 (WS2A) in humans, an autosomal dominant disorder consisting of deafness and hypopigmentation [4].
• The beta3A subunit gene (Ap3b1) of the AP-3 adaptor complex is altered in the mouse hypopigmentation mutant pearl, a model for Hermansky-Pudlak syndrome and night blindness [5].

Psychiatry related information on Hypopigmentation

• Patients with PKU show increased L-phenylalanine in blood, which leads to mental retardation and hypopigmentation of skin and hair [6].
• Penile shaft hypopigmentation: lichen sclerosus occurring after the initiation of alprostadil intracavernous injections for erectile dysfunction [7].

High impact information on Hypopigmentation

• Ocular albinism type 1 (OA1) is an X-linked disorder characterized by severe impairment of visual acuity, retinal hypopigmentation and the presence of macromelanosomes [8].
• Antibody-dependent immunity against the melanosome membrane glycoprotein gp75/tyrosinase-related protein-1 (TYRP-1) of melanocytes leads to autoimmune hypopigmentation (vitiligo) in mice [9].
• Mice doubly deficient in both Fc gamma R gamma and C3 did not develop hypopigmentation, suggesting that complement and Fc gamma R formed redundant mechanisms [9].
• Hypopigmentation occurred in mice deficient in activating FcR containing the common gamma subunit (Fc gamma R gamma(-/-)) and in mice deficient in the C3 complement component [9].
• Griscelli syndrome restricted to hypopigmentation results from a melanophilin defect (GS3) or a MYO5A F-exon deletion (GS1) [10].

Chemical compound and disease context of Hypopigmentation

• Hairbulb tyrosinase activity and glutathione content, as well as urine cysteinyldopa excretion, were low in PWS individuals with and without hypopigmentation and did not separate these two groups [11].
• The mother has patchy fundal hypopigmentation consistent with random X inactivation in an OA1 carrier [12].
• Although the molecular mechanisms which underlie this phenotype remain obscure, it has been postulated that mutations in p result in defective tyrosine transport into murine melanosomes, resulting in hypopigmentation and diminished coat color [13].
• Other, less frequent manifestations are hypopigmentation of the hair, hypotonia, impaired growth, increased incidence of infections, alterations of phagocytic capacity of the neutrophils, abnormalities of cholesterol and glucose metabolism, and cardiovascular alterations [14].
• The parapapillary chorioretinal atrophy was divided into a peripheral zone "Alpha" with irregular hyper- and hypopigmentation, and a more central zone "Beta" characterized by whitish colour, visible large choroidal vessels and visible sclera [15].

Biological context of Hypopigmentation

• Two human diseases of platelet storage pool deficiency (SPD), Hermansky-Pudlak syndrome and Chediak-Higashi syndrome, are recessively inherited disorders characterized by hypopigmentation, prolonged bleeding, and normal platelet counts accompanied by a reduction in dense granule number [16].
• Melanoma patients who developed hypopigmentation and had improved survival after polyvalent melanoma cell vaccine had significantly augmented anti-TRP-2 antibody responses compared with patients with poor prognosis [17].
• Fourth, mice that are double heterozygous for loss-of-function mutations in Sox10 and Ednrb do not demonstrate synergistically increased hypopigmentation compared to mice that are single heterozygotes for either mutation alone, suggesting a lack of direct genetic interaction between these genes [18].
• We report on a girl with apparent hypomelanosis of Ito (ITO); cytogenetic studies disclosed the karyotype 46,X,t(X;10)(p11;q11)mat [19].
• Moreover, the specific ERK pathway inhibitor, PD98059, blocked the hypopigmentation effect of SPC, and abrogated the SPC-mediated downregulation of MITF [20].

Anatomical context of Hypopigmentation

• Of 100 vitiligo patients, 23% showed hypopigmented sports on the iris, 18% pigmentation on anterior chamber, 9% retinal pigment epithelium hypopigmentation, 5% uveitis, 11% had chorioretinal degeneration and 34% had no ocular findings [21].
• We present a patient with incontinentia pigmenti achromians in whom the ocular abnormalities included the commonly reported exotropia, myopia, small optic nerve, and hypopigmentation of the fundus, as well as rarely reported corneal asymmetry, pannus, and atropic irides with irregular pupillary margins [22].
• Successful repigmentation was achieved in 6 patients with three types of hypomelanosis (vitiligo, piebaldism, and albinism) by transplantation of fresh, autologous cultured epithelium with melanocytes [23].
• Interestingly, we observed urinary tract abnormality in the younger HPS sister and a porencephalic cyst in the older HPS sister; both of these developmental defects have been reported in the Cross syndrome (or oculocerebral hypopigmentation syndrome) [24].
• Antibodies to the B16 melanoma cell line and to tyrosinase have been recently defined in our laboratory in sera of patients with vitiligo, melanoma, melanoma-associated hypopigmentation (MAH), and in healthy subjects [25].

Gene context of Hypopigmentation

• We herein present genetic and functional evidence that a third form of GS (GS3), whose expression is restricted to the characteristic hypopigmentation of GS, results from mutation in the gene that encodes melanophilin (Mlph), the ortholog of the gene mutated in leaden mice [10].
• These findings expand the molecular diagnosis of HPS, provide a screening method for a mutation common among Jews, and suggest that other patients with mild hypopigmentation and decreased vision should be examined for HPS [2].
• While PTU is frequently used to induce hypopigmentation in biological systems, little is known about its effects on tyrosinase and other melanogenic proteins [26].
• HPS-3 manifests with mild hypopigmentation and bleeding [27].
• A molecular analysis of the yemenite deaf-blind hypopigmentation syndrome: SOX10 dysfunction causes different neurocristopathies [28].

Analytical, diagnostic and therapeutic context of Hypopigmentation

• The differential diagnosis of the guttate leukoderma of TSC includes several clinical entities such as idiopathic guttate hypomelanosis, disseminated hypopigmented keratoses, and dyschromic amyloidosis [29].
• The development of linear hypopigmentation after intralesional or intraarticular injection of triamcinolone acetonide has been reported in the literature as a very rare side effect [30].
• INTRODUCTION: Patients with albinism have varying degrees of reduced vision, strabismus, iris transillumination, nystagmus, fundus hypopigmentation, and foveal hypoplasia [31].

References