Biomedical subjects

Maria Teresa Seixas

Publications and source records attributed to Maria Teresa Seixas.

3 recordsLinked to original sources

PubMed2006

Hemoglobin Loves Park [beta68 (E12) Leu-->Phe]: report of five cases including one originating from a de novo mutation.

Hemoglobin (Hb) Loves Park [beta68 (E12) Leu-->Phe] was identified in a 2-year-old Portuguese boy with anemia, microcytosis, and hypochromia. This Hb variant was detected by isoelectric focusing and quantified by reverse-phase high-performance liquid chromatography (HPLC) (48.4%), and the DNA mutation was identified by HBB (beta-globin gene) sequencing. Hematological and biochemical analyses performed on his parents revealed normal hematological parameters and normal hemoglobin and globin chain profiles. DNA sequence analysis of the HBB gene of both parents showed the absence of the Hb Loves Park mutation. Study of the haplotypes in the beta-globin gene cluster confirmed parenthood. Moreover, paternity was confirmed by the study of nine short tandem repeats (STRs) and four variable-number tandem repeat (VNTRs) loci. The most likely explanation for these results is that the Hb Loves Park mutation has occurred de novo in this family. The original American cases of Hb Loves Park, from a family of Italian origin, which were never published, as well as two additional cases, are also included in this report. Functional studies revealed that Hb Loves Park is stable and has a decreased oxygen affinity.

Amino Acid Substitution↗

PubMed2005

[Orbital granulocytic sarcoma: case report].

Orbital granulocytic sarcoma is a localized tumor consisting of malignant cells of myeloid origin. This tumor may present in association with acute myelogenous leukemia. Granulocytic sarcoma may be found in a variety of locations throughout the body including the orbit and typically affects children and young adults. There is a slight male predominance in these cases. This is an uncommon case report of a 33-year-old Latin-American woman who was admitted to the Hospital for rapidly progressive orbital proptosis. There was no systemic manifestation of leukemia. The occurrence of orbital granulocytic sarcoma before the development of systemic leukemia in children and young adults is not uncommon and these cases frequently develop hematological evidence within 2 months after initial orbital disease. In this case report, there was no systemic manifestation of leukemia in the last 30 months, even in the presence of orbital tumors. Granulocytic sarcoma is most frequently confused with malignant lymphoma, rhabdomyosarcoma and neuroblastoma. The differential diagnosis of these cases can be challenging, particularly when there is no evidence of systemic leukemia, when imaging features are not sufficiently specific to distinguish granulocytic neoplasms from other tumors. To establish the diagnosis often a biopsy is required. The treatment in such cases (orbital granulocytic sarcoma) is not standardized. Orbital granulocytic sarcoma may be suspected in cases of orbital tumors even in the absence of systemic manifestations of leukemia at any age.

Acute Disease↗

PubMed2004

Hb Yaoundé [beta134(H12)Val-->Ala] in association with Hb C [beta6(A3)Glu-->Lys] in a Caucasian Portuguese family.

Hb Yaoundé [beta134(H12)Val-->Ala] is a rare, silent and asymptomatic hemoglobin (Hb) variant. It was previously reported in a Black man from Cameroon, in association with Hb Kenitra [beta69(E13)Gly-->Arg], and was subsequently found and described as Hb Mataro in a sub-Saharan child. To date, Hb Yaoundé has not been described in Caucasian people and molecular studies have never been performed. Here we describe a three-generation Caucasian Portuguese family in whom Hb Yaoundé was found in association with Hb C [beta6(A3)Glu-->Lys] (in the proband) and in a heterozygous state (in the proband's mother). The Hb studies of the proband's hemolysate, performed by isoelectric focusing (IEF) and low-pressure cation exchange chromatography, only revealed an Hb variant identified as Hb C by comparison with a control. However, analysis performed by reversed-phase high-performance liquid chromatography (HPLC) showed two different beta chain variants and a complete absence of the normal beta chain. This uncommon Hb variant was identified as Hb Yaoundé by DNA sequencing analysis of the beta-globin gene (codon 134, GTG-->GCG). The beta-globin gene haplotypes were determined in all family members using polymerase chain reaction (PCR)-based methodology; Hb Yaoundé was found to be associated with the Mediterranean haplotype II. This study is the first description of Hb Yaoundé in Caucasian individuals, and its association with a Mediterranean haplotype supports the hypothesis of an independent genetic origin other than African.

Chromatography, Ion Exchange↗