Defective neutrophil mobility in the May-Hegglin anomaly

The gene for May-Hegglin anomaly localizes to a <1-Mb region on chromosome 22q12.3-13.1

The May-Hegglin anomaly (MHA) is an autosomal dominant platelet disorder of unknown etiology. It is characterized by thrombocytopenia, giant platelets, and leukocyte inclusion bodies, and affected heterozygotes are predisposed to bleeding episodes. The MHA gene has recently been localized, by means of linkage analysis, to a 13.6-cM region on chromosome 22, and the complete chromosome 22 sequence has been reported. We recently performed a genome scan for the MHA gene in 29 members of a large, multigenerational Italian family, and we now confirm that the MHA locus is on chromosome 22q12. 3-13.1. The maximal two-point LOD score of 4.50 was achieved with the use of marker D22S283, at a recombination fraction of.05. Haplotype analysis narrowed the MHA critical region to 6.6 cM between markers D22S683 and D22S1177. It is of note that the chromosome 22 sequence allowed all markers to be ordered correctly, identified all the candidate genes and predicted genes, and specifically determined the physical size of the MHA region to be 0. 7 Mb. These results significantly narrow the region in which the MHA gene is located, and they represent the first use of chromosome 22 data to positionally clone a disease gene.

Inherited giant platelet disorders. Classification and literature review

Inherited giant platelet disorders are extremely rare. The aim of this article is to review the clinical and laboratory features of this heterogeneous group and to arrive at a working classification. We conducted our literature search using the National Library of Medicine database. A total of 12 clinical entities were described. We classified them into 4 groups depending on the clinical and structural abnormalities. The pathophysiology of these disorders is largely unknown, and more research is needed, particularly in the light of recent advances in laboratory medicine. This review may provide a valuable reference for clinicians and may form a basis for future classification and research.

A morphologic variant of May-Hegglin anomaly in a Chinese girl

An 8 yr old Chinese girl was investigated for easy bruising and mild thrombocytopenia. Platelet aggregation studies and coagulation tests were found to be normal. The giant platelets and Döhle-like cytoplasmic inclusions in granulocytes confirmed the diagnosis of May-Hegglin anomaly. The father's granulocytes also had Döhle-like inclusions and one paternal aunt had a history of bleeding tendency. Review of literature showed that such Döhle-like inclusions had always been described morphologically as crescentic or spindle-shaped. In this case, however, the shape was roundish, oval or poorly defined. Ultrastructurally, the classic description was electron-dense long rods and needles orientating along the long axis of the "spindle". In this case, the only electron-dense particles were dot-like with a haphazard arrangement.

May-Hegglin anomaly: a rare cause of thrombocytopenia

A family with four and an unrelated family with three individuals affected by the May-Hegglin anomaly are described. Platelet counts were markedly reduced and were correctly determined only in the counting chamber. Bleeding time and platelet aggregation were always normal, but platelet nucleotide concentrations (ATP and ADP) were elevated. The platelet glycoprotein complexes Ib/IX, IIb/IIIa and Ia/IIa were quantitatively normal. Platelet-associated IgG was slightly elevated, although thrombocytopenia was presumably not caused by an immunological mechanism. Morphological investigations showed giant platelets and spindle-shaped inclusion bodies in the granulocytes, while their function (phagocytic capacity, radical production) was normal. To exclude hereditary types of thrombocytopenia, morphological and family investigations are required to avoid misdiagnosis with far-reaching diagnostic and therapeutic consequences.

Coincidental finding of May-Hegglin anomaly in a patient with end-stage renal failure

We present two cases of May-Hegglin anomaly incidentally discovered in a patient and his brother during investigation of the patient for end-stage renal failure and workup for renal transplantation. Routine laboratory tests were performed and included a basically normal clotting profile. Ultrastructural studies of the May-Hegglin inclusions proved diagnostic, findings were compared with those of two similar granulocyte inclusion bodies, and nomenclature discrepancies that still exist in most references are again emphasized. The finding of the May-Hegglin anomaly in our patient appears to be incidental to the underlying renal disease. A successful renal transplant has been carried out in this patient. We now report on a patient and his brother in which the MHA was discovered during workup of the patient for end-stage renal failure and renal transplantation. No association between the underlying renal disease and the MHA could be demonstrated.

Hereditary types of thrombocytopenia with giant platelets and inclusion bodies in the leukocytes

Three forms of hereditary thrombocytopenia with giant platelets and inclusion bodies in the leukocytes have thus far been recognized. The May-Hegglin anomaly is characterized by giant platelets and spindle-shaped inclusion bodies in the leukocytes, which consist of 7-10 nm parallel-lying filaments. The Fechtner syndrome is a variant of the Alport syndrome, with inclusion bodies consisting of dispersed filaments, ribosomes and a few segments of rough and smooth endoplasmic reticulum. The Sebastian platelet syndrome shows the same platelet and leukocyte morphology observed in the Fechtner syndrome, but the additional anomalies e.g., the Alport syndrome, are lacking. The clinical signs and symptoms are variable. Most patients show only a mild bleeding tendency or are asymptomatic, but cases of severe postoperative hemorrhage have also been reported. Platelets can vary greatly in number, but are usually in the range of 20,000 to 120,000 platelets/microliters, showing a mean platelet volume of 15-20 fl, unimpaired in vitro function and, in addition to their size and unorganized microtubular system, normal morphology. To date, no platelet membrane defects have been defined. Because the megakaryocyte number and platelet kinetics are normal, the pathogenesis of thrombocytopenia in these giant platelet syndromes is unresolved; this is also true of the leukocyte inclusion bodies. Because of the ubiquity of electronic particle counters, asymptomatic patients are increasingly being identified, but they are often misdiagnosed as having autoimmune thrombocytopenia.

In vivo crevicular leucocyte response in humans to a chemotactic challenge. Effects of periodontal diseases

An in vivo assay was recently developed to monitor the crevicular leucocyte response to chemotactic agents, e.g., casein and N-formyl peptides. This method was used to monitor humans with little or no gingival disease (C group), gingivitis (G group), chronic periodontitis (CP group) and localized juvenile periodontitis (LJP group). Casein (0.2 microliters, 2 mg/ml) was placed into an isolated gingival crevice of each subject with a calibrated wire loop and the time recorded (t = 0). Leucocytes were counted in crevicular washes (10 microliters) 15 minutes later and every 5 minutes thereafter up to t = 50 minutes. This protocol was repeated for the crevice of an adjacent tooth except that the crevicular fluid flow response to the chemotactic challenge was monitored. The C, G and CP subjects showed a similar pattern of response to the chemoattractant with a single "peak" of leucocytes at approximately t = 25 minutes. However, the peak cell count was much greater in the G and CP groups than in the C group. LJPs showed an abnormal pattern with two leucocyte peaks, one at approximately 25 minutes and the other at 45 minutes. Both peaks tended to be higher than the single peak seen in Cs but were significantly lower than that in Gs or CPs, even at similar levels of inflammation. In addition, the peak leucocyte response (to casein) in LJPs did not increase with increasing leucocyte counts in the unchallenged (resting) crevice, whereas a positive relationship was seen in the other groups of subjects. These data suggest that this new assay may provide important diagnostic information on in vivo neutrophil migration in the gingival crevice and on susceptibility to periodontal disease.