A novel termination codon mutation of the WAS gene in a Thai family with Wiskott-Aldrich syndrome

Wiskott-Aldrich syndrome (WAS) is an X-linked recessive disorder characterized by microthrombocytopenia, eczema, immunodeficiency, and susceptibility to lymphoid malignancy. Loss-of-function mutations in WAS gene have been identified to cause disorders with platelet defects including WAS and X-linked thrombocytopenia. Mutations anticipated to yield truncated or no protein have been associated with the more severe presentations of WAS. Activating mutations in WAS gene result in an entirely different phenotype, an X-linked severe congenital neutropenia. We describe a Thai family with classic WAS. The proband, a one-year-old boy presented with recurrent mucous bloody diarrhea, recurrent otitis media, chronic eczema, thrombocytopenia, and small platelet sizes. The patient's older brother who also had persistent thrombocytopenia died at the age of seven months from severe pneumonia. Immunoblot analysis demonstrated that the proband's cells lacked WAS protein expression. Mutation analysis of the proband and his mother for the entire coding region of WAS identified a novel type of mutation, a termination codon mutation, X503R. The change is expected to result in an elongated mRNA that would code for a WASP of 581 amino acid residues instead of the normal 502 residues. Because of the absence of WASP expression, we speculate that the termination codon mutation causes reduced mRNA stability. Our findings supported that WAS mutations resulted in no protein are associated with a severe phenotype of WAS.     

Food induced urticaria in children

We conducted a prospective study at King Chulalongkorn Memorial Hospital, from June 2001 to November 2003, to identify the contribution of food allergy to urticaria in children. During the study period, 100 children with urticaria were enrolled, 36 of whom had a history suspicious of food allergy. Fifteen of 100 patients had fever (9 from upper respiratory tract infections, 4 from diarrhea and 2 from skin infections). A skin prick test (SPT) was positive in 15 of the 36 children who were suspected of having food allergy; 5 patients out of the positive SPT group had anaphylaxis due to food (2 from cow milk, 2 from wheat and 1 from egg). Six patients in the positive SPT group had a negative food challenge test (4 from open challenges and 2 from double-blind placebo-controlled food challenges [DBPCFC]). The other 4 patients of the positive SPT group refused the food challenge test. The parents of a patient who had urticaria from egg refused the skin prick test; an oral challenge test confirmed the diagnosis of egg allergy. One of the 21 patients that had a negative SPT had shrimp allergy proven by DBPCFC. Of the 64 patients who had no history related to food, SPT was done in 27 patients and revealed a positive result in 7 patients, all of whom had a negative food challenge test (4 with open challenge and 3 with DBPCFC). Urticaria from food was found in 7% and was suspected in another 4% of the patients. Severe reactions to food like anaphylaxis may occur. SPT alone is not adequate in making the diagnosis of food allergy; it must be confirmed by a food challenge test. Thirty percent of patients that did not have a history related to food had false positive SPT. Without a history suspicious of food allergy, SPT yields only minimal benefit.     

B-cell epitopes as a screening instrument for persistent cow's milk allergy

BACKGROUND: Cow's milk is one of the most common causes of food allergy in the first years of life. We recently defined IgE-binding epitopes of all 6 major cow's milk proteins (alpha(s1)-, alpha(s2)-, beta-, and kappa-casein; alpha-lactalbumin; and beta-lactoglobulin) and had some evidence suggesting that IgE antibodies from patients with persistent cow's milk allergy (CMA) recognize different epitopes on cow's milk proteins than do those from patients who were likely to outgrow their allergy. OBJECTIVE: In this study we sought to assess whether recognition of IgE antibodies of certain epitopes of cow's milk proteins would clearly separate the patients with life-long CMA from those who will become clinically tolerant to cow's milk. METHODS: According to the known IgE-binding regions of cow's milk proteins, 25 decapeptides of alpha(s1)-casein, alpha(s2)-casein, kappa-casein, alpha-lactalbumin, and beta-lactoglobulin, comprising the core epitopes, were synthesized on a cellulose-derivatized membrane. Sera from 10 patients with persistent CMA and 10 patients who subsequently outgrew their milk allergy were used to investigate the differences in epitope recognition. RESULTS: Five IgE-binding epitopes (2 on alpha(s1)-casein, 1 on alpha(s2)-casein, and 2 on kappa-casein) were not recognized by any of the patients with transient CMA but showed binding by the majority of the patients with persistent allergy. The presence of IgE antibodies against at least 1 of 3 epitopes (amino acid [AA] 123-132 on alpha(s1)-casein, AA 171-180 on alpha(s2)-casein, and AA 155-164 on kappa-casein) identified all patients with persistent CMA. CONCLUSIONS: The presence of IgE antibodies to distinct allergenic epitopes of cow's milk proteins can be used as a marker of persistent CMA. Prospective studies are needed to investigate the usefulness of these informative epitopes in predicting life-long CMA in young children.     

Characterizing the general surgery workforce in rural America

BACKGROUND: General surgeons form a crucial component of the medical workforce in rural areas of the United States. Any decline in their numbers could have profound effects on access to adequate health care in such areas. HYPOTHESIS: We hypothesize that the rural areas of the United States are relatively undersupplied with general surgeons. DESIGN AND SETTING: The American Medical Association's Physician Masterfile was used to identify all clinically active general surgeons as well as their locations and characteristics. Their geographic distribution was examined using the ZIP code version of the Rural-Urban Commuting Areas. Surgeons were classified as practicing in urban areas, large rural areas, or small/isolated rural areas. RESULTS: There are currently 17 243 general surgeons practicing in the United States. Nationally, the number of general surgeons per population of 100 000 varies from 6.53 in urban areas to 7.71 in large rural areas and 4.67 in small/isolated rural areas. Only 10.6% of the nation's general surgeons are female. Wide variations in numbers of general surgeons were found between and within individual states. General surgeons in the smallest rural areas are more likely than those in urban areas to be male (92.7% vs 88.3%, P<.001), 50 years of age or older (51.6% vs 42.1%, P<.001), or international medical graduates (25.2% vs 20.1%, P<.001). CONCLUSIONS: The overall size of the rural general surgical workforce has remained static over the last decade, but its demographic characteristics suggest that numbers will decline. Many rural residents have limited access to surgical services. Steps to reverse this trend are needed to preserve the viability of health care in many parts of rural America.     

In vitro Correction of a Novel Splicing Alteration in the BTK Gene by Using Antisense Morpholino Oligonucleotides

A novel sequence variant, c.240+109C>A, in the Bruton’s tyrosine kinase (BTK) gene was identified in a patient with X-linked agammaglobulinemia. This alteration resulted in an incorporation of 106 nucleotides of BTK intron 3 into its mRNA. Administration of the 25-mer antisense morpholino oligonucleotide analog in the patient’s cultured peripheral blood mononuclear cells was able to restore correctly spliced BTK mRNA, a potential treatment for X-linked agammaglobulinemia.