- Author: Robert A Schwartz, MD, MPH; Chief Editor: Dirk M Elston, MD more...
Monilethrix is an autosomal dominant disorder characterized by a beaded appearance of the hair due to periodic thinning of the shaft. The phenotype results in hair fragility and patchy dystrophic alopecia. The term monilethrix is derived from monile (Latin), which means necklace, and thrix (Greek), which means hair. This term indicates the resemblance of the hair to a string of beads or a necklace. Monilethrix is also known as nodose hair.
In 1897, Walter Smith first described monilethrix (pili moniliformes [Latin]). Regular nodes and internodes that lead to breakage of the hair and varying degrees of alopecia characterize this hair-shaft anomaly. Monilethrix is inherited as an autosomal dominant trait with high penetrance but variable expressivity. However, autosomal recessive inheritance for this disease has been sporadically reported. Note the images below.
The etiology of monilethrix remains obscure. Results of genetic linkage analysis suggest that monilethrix is likely caused by a mutation in a hair keratin. Mutations in the human hair basic keratins hHb1 and hHb6 have been described with this disorder.[2, 3] The most frequent mutation is the E413K mutation in hHb6. In a study of a large family from Turkey with 11 affected members, the mutation (E402K) in exon 7 of the KRT86 gene was identified as etiologic.
These mutations in the helix-encoding region in the hair-specific keratins hHb1 and hHb6 may represent different novel heterozygous point mutations of the same codon in exon 7 of the hHb6 gene. A mutational hotspot may exist in the helix termination motif of hHb6. A missense mutation in the type II hair keratin hHb3 has been shown to be associated with monilethrix. Analysis for gene mutation in a Chinese mother and her daughter with monilethrix revealed heterozygous transition of c.1204G to A (p.E402K) of hHB6 and demonstrated that affected family members carried the p.E402K mutation. Twenty-one affected individuals in 2 unrelated monilethrix families of Indian origin were studied, and a point mutation (g.4624G>A) in the HTM motif (exon-7) of the KRTHB6 gene was found in all the affected members, leading to E413K change in this basic keratin.
An autosomal recessive form of monilethrix was found to be caused by mutations in DSG4 while evaluating 12 Jewish families from Iraq, Iran, and Morocco, with microscopic findings of monilethrix, but with no evidence of vertical transmission. Sequencing of the main candidate gene from this region revealed 4 different mutations in desmoglein 4 (DSG4). To date, whether monilethrix is a disorder of the function or structure of the hair has not been determined. Recent data imply that the pathogenesis of monilethrix is related to dysfunctional mutated DSG4 undergoing degradation, with unfolded protein response induction. A novel D323G mutation of the DSG4 gene was evident in a child with localized autosomal recessive hypotrichosis overlapped with monilethrix.
Autosomal dominant monilethrix is caused by mutations in hair keratin genes KRT81, KRT83, or KRT86, whereas the autosomal recessive form results from mutations in the desmoglein 4 gene (DSG4). Compound heterozygous mutations in the DSG4 gene may occur.
Congenital monilethrix and hereditary unilateral external auditory canal atresia were found to be co-inherited in a Chinese pedigree with recurrent KRT86 mutation.
No data are available.
No racial predilection is evident for monilethrix. Monilethrix is not linked to any particular hair color.
No sex limitation is evident for monilethrix.
The onset of monilethrix is during infancy.
Monilethrix is a lifelong disease. Symptoms spontaneously regress during puberty and pregnancy, but the condition never disappears completely.
Zlotogorski A, Marek D, Horev L, Abu A, Ben-Amitai D, Gerad L, et al. An autosomal recessive form of monilethrix is caused by mutations in DSG4: clinical overlap with localized autosomal recessive hypotrichosis. J Invest Dermatol. 2006 Jun. 126(6):1292-6. [Medline].
Korge BP, Hamm H, Jury CS, Traupe H, Irvine AD, Healy E, et al. Identification of novel mutations in basic hair keratins hHb1 and hHb6 in monilethrix: implications for protein structure and clinical phenotype. J Invest Dermatol. 1999 Oct. 113(4):607-12. [Medline].
Winter H, Vabres P, Larregue M, Rogers MA, Schweizer J. A novel missense mutation, A118E, in the helix initiation motif of the type II hair cortex keratin hHb6, causing monilethrix. Hum Hered. 2000 Sep-Oct. 50(5):322-4. [Medline].
Muramatsu S, Kimura T, Ueki R, Tsuboi R, Ikeda S, Ogawa H. Recurrent E413K mutation of hHb6 in a Japanese family with monilethrix. Dermatology. 2003. 206(4):338-40. [Medline].
Celep F, Uzumcu A, Sonmez FM, Uyguner O, Balci YI, Bahadir S, et al. Pitfalls of mapping a large Turkish consanguineous family with vertical monilethrix inheritance. Genet Couns. 2009. 20(1):1-8. [Medline].
Pearce EG, Smith SK, Lanigan SW, Bowden PE. Two different mutations in the same codon of a type II hair keratin (hHb6) in patients with monilethrix. J Invest Dermatol. 1999 Dec. 113(6):1123-7. [Medline].
Horev L, Glaser B, Metzker A, Ben-Amitai D, Vardy D, Zlotogorski A. Monilethrix: mutational hotspot in the helix termination motif of the human hair basic keratin 6. Hum Hered. 2000 Sep-Oct. 50(5):325-30. [Medline].
van Steensel MA, Steijlen PM, Bladergroen RS, Vermeer M, van Geel M. A missense mutation in the type II hair keratin hHb3 is associated with monilethrix. J Med Genet. 2005 Mar. 42(3):e19. [Medline].
Feng A, Liu P, Yang T, Wang Y, Chen X, Liu M, et al. [Analysis of human hair basic keratin 6 gene mutation in a Chinese Han family with monilethrix.]. Zhonghua Yi Xue Yi Chuan Xue Za Zhi. 2008 Apr. 25(2):141-4. [Medline].
Khandpur S, Bairwa NK, Reddy BS, Bamezai R. A study of phenotypic correlation with the genotypic status of HTM regions of KRTHB6 and KRTHB1 genes in monilethrix families of Indian origin. Ann Genet. 2004 Jan-Mar. 47(1):77-84. [Medline].
Kato M, Shimizu A, Yokoyama Y, Kaira K, Shimomura Y, Ishida-Yamamoto A, et al. An autosomal recessive mutation of DSG4 causes monilethrix through the ER stress response. J Invest Dermatol. 2015 May. 135 (5):1253-60. [Medline].
Wang JM, Xiao YJ, Liang YH. Novel D323G mutation of DSG4 gene in a girl with localized autosomal recessive hypotrichosis clinically overlapped with monilethrix. Int J Dermatol. 2015 Oct. 54 (10):1163-8. [Medline].
van Steensel M, Vreeburg M, Urbina MT, López P, Morice-Picard F, van Geel M. Novel KRT83 and KRT86 mutations associated with monilethrix. Exp Dermatol. 2015 Mar. 24 (3):222-4. [Medline].
Farooq M, Ito M, Naito M, Shimomura Y. A case of monilethrix caused by novel compound heterozygous mutations in the desmoglein 4 (DSG4) gene. Br J Dermatol. 2011 Apr 18. [Medline].
Feng YG, Xiao SX, Xu AL, Feng JY, Wang JM. Congenital monilethrix and hereditary unilateral external auditory canal atresia are co-inherited in a Chinese pedigree with recurrent KRT86 mutation. J Dermatol. 2012 May 9. [Medline].
Leitner C, Cheung S, de Berker D. Pitfalls and Pearls in the Diagnosis of Monilethrix. Pediatr Dermatol. 2013 Jul 9. [Medline].
Ullah A, Raza SI, Ali RH, Naveed AK, Jan A, Rizvi SD, et al. A novel deletion mutation in the DSG4 gene underlies autosomal recessive hypotrichosis with variable phenotype in two unrelated consanguineous families. Clin Exp Dermatol. 2014 Sep 23. [Medline].
Rakowska A, Slowinska M, Czuwara J, Olszewska M, Rudnicka L. Dermoscopy as a tool for rapid diagnosis of monilethrix. J Drugs Dermatol. 2007 Feb. 6(2):222-4. [Medline].
Liu CI, Hsu CH. Rapid diagnosis of monilethrix using dermoscopy. Br J Dermatol. 2008 Sep. 159(3):741-3. [Medline].
Wallace MP, de Berker DA. Hair diagnoses and signs: the use of dermatoscopy. Clin Exp Dermatol. 2010 Jan. 35(1):41-6. [Medline].
Sharma VK, Chiramel MJ, Rao A. Dermoscopy: A rapid bedside tool to assess monilethrix. Indian J Dermatol Venereol Leprol. 2016 Jan-Feb. 82 (1):73-4. [Medline].
Rudnicka L, Olszewska M, Rakowska A, Kowalska-Oledzka E, Slowinska M. Trichoscopy: a new method for diagnosing hair loss. J Drugs Dermatol. 2008 Jul. 7(7):651-4. [Medline].
Landau M, Brenner S, Metzker A. Medical Pearl: an easy way to diagnose severe neonatal monilethrix. J Am Acad Dermatol. 2002 Jan. 46(1):111-2. [Medline].
Karincaoglu Y, Coskun BK, Seyhan ME, Bayram N. Monilethrix: improvement with acitretin. Am J Clin Dermatol. 2005. 6(6):407-10. [Medline].
Rossi A, Iorio A, Scali E, et al. Monilethrix treated with Minoxidil. Int J Immunopathol Pharmacol. 2011 Jan-Mar. 24(1):239-42. [Medline].
Mallory SB, Leal-Khouri S. All Illustrated Dictionary of Dermatologic Syndromes. London, England: Parthenon Publishing; 1994. Vol 143: 95.
Orfanos CE, Happle R. Hair and Hair Diseases. New York, NY: Springer Verlag; 1990. Vol 16: 423-31.