RESUMO
We have observed that the fragile hair of two untreated patients with argininosuccinic aciduria showed abnormal alternating zones of bright and dark banding by polarizing microscopy. Scanning electron microscopy documented discontinuous grooves with a 50 to 100 microns periodicity. Results of amino acid analysis of the hair were essentially normal. After the patients were treated with a low-protein, arginine-supplemented diet, the hair assumed a normal appearance. Five patients already treated with diet showed no hair abnormalities. The pathogenesis of the hair changes in unknown, but our findings suggest that products generated in the disease can adversely affect metabolically active tissue such as hair.
Assuntos
Erros Inatos do Metabolismo dos Aminoácidos/dietoterapia , Acidúria Argininossuccínica , Cabelo/anormalidades , Aminoácidos/análise , Argininossuccinato Liase/sangue , Ácido Argininossuccínico/sangue , Ácido Argininossuccínico/urina , Pré-Escolar , Genes Recessivos/genética , Cabelo/química , Cabelo/ultraestrutura , Humanos , Lactente , Masculino , Microscopia Eletrônica , Microscopia de PolarizaçãoRESUMO
BACKGROUND: Some hereditary palmoplantar keratodermas (PPK) have been defined at the molecular level. OBJECTIVE: Our purpose was to establish the cause of a hereditary PPK with unique histopathologic findings in the epidermis. METHODS: Investigative studies included light and electron microscopy and determination of genomic DNA sequence. RESULTS: Six patients with PPK were found to have unique changes in the epidermis characterized by orthokeratosis, parakeratosis, perinuclear vacuolization, and keratohyalin granules that varied in size and shape and were located in the cell periphery. Electron microscopy showed the perinuclear region contained many ribosomes and vacuoles and was surrounded by a tonofibril shell. Family involvement suggested a dominant disorder. However, no mutation of keratin genes 1, 6a, 9, or 16 was found. CONCLUSION: The histopathologic features of this unique PPK most closely resemble Curth-Macklin ichthyosis for which the genetic basis has not been established. Further genetic studies are needed.
Assuntos
Ceratodermia Palmar e Plantar/patologia , Biópsia , Diagnóstico Diferencial , Feminino , Humanos , Hiperceratose Epidermolítica/diagnóstico , Queratinas/genética , Ceratodermia Palmar e Plantar/diagnóstico , Ceratodermia Palmar e Plantar/genética , Ceratodermia Palmar e Plantar Difusa/patologia , Masculino , Mutação Puntual , Pele/patologia , Pele/ultraestruturaRESUMO
Ichthyosis bullosa of Siemens (IBS) is a rare disorder of cornification characterized by blister formation in the upper suprabasal layers of the epidermis. Molecular analysis of IBS has identified mutations in the keratin 2e (K2e) gene, which is located in the type II keratin gene cluster on chromosome 12q. We have studied two IBS families and have identified heterozygous point mutations in codon 493 of the K2e gene in both families. Whereas a non-conservative amino acid substitution at position 117 of the 2B region of K2e (E117K) was associated with a severe phenotype in family 1, family 2 showed mild clinical features as a result of a conservative substitution (E117D). These data suggest a phenotype-genotype correlation in these families.