Clinical features of Mexican patients with Mucopolysaccharidosis type I.

Mucopolysaccharidosis type I (MPS-I) is an autosomal recessive lysosomal storage disorder caused by a deficiency or absence of α--iduronidase, which is involved in the catabolism of glycosaminoglycans (GAGs). This deficiency leads to the accumulation of GAGs in several organs. Given the wide spectrum of the disease, MPS-I has historically been classified into 3 clinical subtypes - severe (Hurler syndrome), intermediate (Hurler-Scheie syndrome), and mild (Scheie syndrome) - none of which is determined by residual enzyme activity. Eleven Mexican patients with MPS-I from northwestern México were evaluated. Diagnoses were confirmed through quantification of GAGs in urine and enzyme assay for α--iduronidase. Regardless of phenotype, all patients had various degrees of infiltrated facies, short stature, dysostosis multiplex, joint contractures, and corneal opacity typical of the disease. A better understanding of the spectrum of this disease can assist in diagnosis, treatment, and improvement in the quality of life for these patients.

Centromeric association of a microchromosome Y in two male patients.

We characterized two Y-ring microchromosomes (MC) found in an azoospermic patient with Turner stigmata (case A) and a male infant with hypospadias (case B). The karyotypes, as assessed by banding, FISH, and STRs/STSs analyses, were 46,X,r(Y).ish r(Y)(p11.3q11.222)(SRY+,DYZ3+) and 46,X,+r(Y)/45,X.ish r(Y)(p 11.2q11.2)(Xp/Yp-,SRY+,DYZ3+) respectively. In both cases, we evaluated the association of each MC with the centromere of the nearest and second nearest chromosomes in G-banded metaphases by means of measuring the intervening distance according to two criteria: < or =1 time or < or =3 times the size of the MC in each metaphase. The case A's MC was associated 84 times in 98 cells according to the latter or less strict criterion and two times in 98 cells according to the strict criterion; the corresponding values for case B were 84 and two in 95 cells respectively. The centromeric association appears to be related to centromeric attraction mediated by heterochromatin or centromere-specific proteins, the replication time, and the Rabl orientation.