Detecting pigmentary hair disorders in children

August 1, 2004

Charleston, S.C.- Hair disorders in children are discernible by several factors, including the amount of hair on the head (hypotrichosis or hypertrichosis), structure (with fragility or without) and color (hypopigmented or hyperpigmented), according to Carola Duran-McKinster, M.D., department of dermatology at the National Institute of Pediatrics in Mexico.

Charleston, S.C.- Hair disorders in children are discernible by several factors, including the amount of hair on the head (hypotrichosis or hypertrichosis), structure (with fragility or without) and color (hypopigmented or hyperpigmented), according to Carola Duran-McKinster, M.D., department of dermatology at the National Institute of Pediatrics in Mexico.

"With normal pigmentation at least 127 genes are involved and nearly half have been cloned," explains Dr. Duran. "Mutations give rise to a decrease or total loss of pigment."

Factors for normal pigmentation include the development and differentiation of melanocytes, transcription factors and growth factors, protein components of the melanosome, and organelle transport.

"Microscopic examination of the hair bulb includes determining if it is in anagen (growth phase of the hair cycle) or telogen (resting phase). For the hair shaft we look for fractures, twisting, nodes, decreased shaft diameter, knotting and also observe the color," she says.

The hair cycle includes several phases: anagen (growth phase of the hair cycle); catagen (a regressing phase of the hair growth cycle when cell proliferation ceases, the hair follicle shortens and an anchored club hair shortens); and telogen (resting phase).

Hypopigmentary hair disorders can be circumscribed or total. "Circumscribed hypopigmentary hair disorders include poliosis, such as piebaldism and Waardenburg's Syndrome, and premature graying. Total hair disorders include albinism (Type 1 A and B, and Type II) and light hair (as with phenylketonuria and Menkes syndrome) or silver hair (as with Chediak-Higashi syndrome, Griscelli syndrome, and Elejalde syndrome)," she explains.

Circumscribed disordersPiebaldism, a mutation in the proto-oncogene KIT, is autosomal-dominant. It is represented by a white forelock, and there is also congenital leukoderma in the forehead, the anterior trunk and extremities.

"Patients have a good prognosis," she notes.

Total disordersOculocutaneous albinism is autosomal recessive. For Type 1 A, symptoms include white hair and pink skin, photophobia and nystagmus, or blindness. Type I B is characterized by yellow hair and slightly tan skin. This is less severe than OCA IA, she explains.

Menkes syndrome, a progressive neurodegenerative process, has four clinical forms. It is X-linked recessive. Symptoms include connective tissue defects, fair skin and Pili torti, as well as thin and light hair.

Phenylketonuria is an autosomal recessive disease that results from a phenylalanine hydroxylase deficiency. Symptoms include hypopigmented skin, and hair, eczema, and/or progressive neurologic alterations. Tyrosine treatment causes darkening, she explains.

According to Dr. Duran, 27 cases of silvery hair syndromes have been treated at the National Institute of Pediatrics in Mexico.

She notes that Chediak-Higashi syndrome is an autosomal-recessive syndrome caused by a mutation of the CR 1 lysosomal trafficking (LYST). Characteristics include fair skin at birth or long-lasting tan, silvery hair, giant granules in neutrophils, and recurrent infections. There is an early death after the "accelerated phase," she reports.

Another autosomal recessive disease, Griscelli syndrome is caused by a mutation in the CR 15 (Rab27a). It is characterized by fair skin at birth or a long-lasting tan, silvery hair and severe immunodeficiency (B and T cells). Most patients develop hemophagocytic syndrome, which often causes an early death, she says.

Dr. Duran says standard treatment for Griscelli syndrome includes IVGG 400 mg/kg monthly and a bone marrow transplant or umbilical cord cell transplant.

Elejalde syndrome is a neuroectodermal melanolysosomal disease that results from a mutation in Cr 15 (Myo5A). Symptoms include fair skin at birth or long-lasting tan, silvery hair, no immunodeficiency, and severe neurological alterations, including hypotonia, hemiplegia, quadriplegia, spasticity and seizures.

"There is a regressive neurological process and currently no treatment," she says. Death results.