PILI TORTI

 

The short and brittle hairs in patients with pili torti, when viewed through a microscope, appear flattened and twisted through 90° to 360°. The twisting must be differentiated from the normal twisting in the hair of black individuals and in the pubic/axillary hairs of other races; the hairs are distinguished by the multiple irregular intervals of twisting along an otherwise straight hair shaft . As with trichorrhexis nodosa, pili torti does not signify a particular abnormality but can be seen in many different syndromes and in the presence of other hair shaft abnormalities. Hereditary pili torti as an isolated finding, usually autosomal dominant, but potentially autosomal recessive or sporadic, is present at birth or develops over the first 2 years of life . Clinically, the patient may have patchy alopecia with coarse stubble or longer broken hairs. The hair abnormality may improve after puberty. Pili torti, or a facsimile best characterized as “twisting hair dystrophy,” may occur with other abnormalities. Particularly notable is the association of pili torti with Menkes syndrome (which results from inherited loss-of-function mutations in the gene encoding a copper-transporting adenosine triphosphatase (Atp7a) on the X chromosome or trichopoliodystrophy. Infants with Menkes syndrome develop sparse, depigmented brittle hairs that show pili torti or trichorrhexis nodosa on microscopic examination. The affected child characteristically has pale, lax skin, and mental and neurologic impairment secondary to degeneration of cerebral, cerebellar, and connective tissue. In this X-linked recessive disorder, the defective gene, MKN or ATP7A, which maps to Xq13.3, encodes a copper-translocating membrane protein adenosine triphosphatase that prevents effective copper transport and leads to the accumulation of intracellular copper in

some tissues. The excessive intracellular copper inappropriately triggers the synthesis of metallothionein, whose normal function is to chelate copper to prevent cellular toxicity. This further deprives the copper-requiring enzymes of the copper needed for normal function. A low serum level of ceruloplasmin is diagnostic. Copper replacement is ineffective in preventing the inevitable progressive and lethal neurologic decline, but copper-histidine given immediately postpartum may prevent or ameliorate the severe neurodegeneration