Screening for ELANE, HAX1 and GFI1 gene mutations in children with neutropenia and clinical characterization of two novel mutations in ELANE gene.

BACKGROUND: Congenital neutropenia is a rare disease. Recurrent infections since young age are the presentation. The most common mutation causing severe congenital neutropenia (SCN) and cyclic neutropenia (CyN) is the ELANE gene. The objectives of this study were to screen the three common genetic mutations of ELANE, HAX1 and GFI1 in children with chronic neutropenia and to describe the clinical characteristics of children who had the mutations. METHODS: Infants having ANC < 1,000/cu mm or children aged > 1 year having ANC < 1,500/cu mm at least 3 times in 3 months were enrolled in the study. Patients who had acquired neutropenia due to infection, immune deficiency, or drugs were excluded. The ELANE gene was first studied; and if mutations were not identified, the HAX1 and GFI1 genes were further examined. RESULTS: A total of 60 patients were enrolled in the study. The median (range) age, ratio of female to male, ANC, and last follow-up age were 9.2 (0.5-45.2) months, 1:1.2, 248 (0-1,101) /cu mm, and 19.9 (3.5-202.3) months, respectively. Infections were noted in 67.3% of all patients. ELANE gene mutation was found in only four patients (6.7%), and the rest (56 patients) showed no mutations in the HAX1 and GFI1 genes. In patients without mutations, 66.0% had normal ANC during the follow-up, with a median (range) age for normal ANC of 19.8 (4.0-60.0) months. Two novel mutations p. Ala79del (c.234_236del) and p. Val197GlufsTer18 (c.589_590insAGGCCGGC) were identified, and they respectively cause SCN and CyN. Patients with the two novel mutations presented with several episodes of infection, including pneumonia, sepsis, abscess, otitis media, and gum infection. CONCLUSION: The genetic screening for ELANE, HAX1, and GFI1 gene mutations in 60 patients with chronic neutropenia could identify four patients (6.7%) with ELANE gene mutation and two novel mutations, p. Ala79del in exon 3 and p. Val197GlufsTer18 in exon 4 causing SCN; and CyN, respectively.

Response to Prolonged Duration of Therapeutic Dose Oral Iron Therapy in a Girl With Novel TMPRSS6 Gene Variants: A Case Report and Review Literature.

Iron-refractory iron deficiency anemia (IRIDA) is an autosomal recessive disorder caused by mutations in the TMPRSS6 gene, which impair iron homeostasis. We reported a 4-year-old girl who presented with a 1-year history of iron deficiency anemia. Her hemoglobin level increased from 6.5 g/dL to 12.6 g/dL with a prolonged duration of therapeutic dose oral iron therapy (5 mg/kg/d), and the level remained quite stable during the therapy. Genetic analysis of the TMPRSS6 gene revealed compound heterozygotes of 2 novel pathogenic variants: c.811C> T (NM_153609.3) in exon 7 (NP_705837: p.R271Ter) and c.1254C> G in exon 11 (p.Y418Ter). The results highlight the significance of genetic investigation and long-term iron therapy in iron-refractory iron deficiency anemia patients.

Three-Decade Successive Establishment of Care for Women/Girls from Families with Haemophilia.

Objective: The study aimed to report a 3-decade successive establishment of care for women/girls from families with haemophilia. Methods: A retrospective analysis was conducted on 462 women/girls from 243 families from 1987 to 2021. Results: Combining phenotypic analysis of coagulation factor and genotypic analysis of either linkage analysis or mutation detection confirmed the status of all obligate haemophilia carriers (A118, B19). For potential carrier, 159 proven carriers (A130, B29) and 146 noncarrier status (A126, B20) were diagnosed except 20 potential carriers (A16, B4). Only 54 prenatal diagnoses were requested resulting in normal males (n = 21), males with haemophilia A (n = 12) and females with either normal or carrier status (n = 21). Additionally, 40 women/girls with haemophilia carrier received a diagnosis of severe haemophilia A with Turner's syndrome (n = 2) and mild haemophilia (A31, B7). The skewed X-chromosome inactivation of the nonmutant factor VIII/IX carrying X-chromosome of 8% (2/25) was found in mild haemophilia. Factor concentrate and desmopressin are prescribed for these affected women/girls. The response of women/girls with either haemophilia carrier or haemophilia was amazement with their religious beliefs and cultural acceptance. Conclusion: Appropriate care for women/girls from families with haemophilia concerning diagnosis and management of haemophilia and carrier has been successively established.

Whole-exome sequencing uncovered genetic diagnosis of severe inherited haemolytic anaemia: Correlation with clinical phenotypes.

Next-generation sequencing has shed light on the diagnosis of previously unsolved cases of inherited haemolytic anaemia (IHA). We employed whole-exome sequencing to explore the molecular diagnostic spectrum of 21 unrelated Thai paediatric patients with non-thalassemic IHA, presenting hydrops fetalis and/or becoming transfusion-dependent for 1 year or more or throughout their lifespan. Anaemia was detected prenatally, within the first month and the fifth year of life in three, 12 and six patients respectively. Molecular diagnosis obtained from all patients revealed SPTB as the most frequently mutated gene (four reported, three novel), found in 31 of 42 studied alleles. The other two mutated genes identified were ANK1 (three novel) and KLF1 (two reported). Four recurring mutations within exon 29/30 (NM_001024858.2) accounted for the vast majority (90%) of mutated SPTB alleles, biallelic inheritance of which resulted in the most severe phenotypes: hydrops fetalis and life-long transfusion dependency. Dominant ANK1 (n = 3) and SPTB (n = 2) mutations and biallelic class 2 KLF1 mutations (n = 1) led to a shorter period of transfusion dependency. Our study demonstrated that mutated SPTB causing red-cell membranopathy is likely the most common cause of severe non-thalassemic IHA among Thai patients. This urges carrier screening in the population to prevent subsequent, severely affected births.

Prominent Mutation of Intron 22 Inversion in Sporadic Hemophilia: Is It Worth the Antenatal Screening?

Background: Adequate replacement for patients with hemophilia is costly, especially in countries with limited resources. Objective: Factor VIII gene mutations among Thai patients with hemophilia A were analyzed for the most common mutation. The cost-effectiveness of finding one female without family history of hemophilia possessing the most common factor VIII mutation was compared with the cost of treating one patient with hemophilia. Methods: In all, 109 unrelated patients with hemophilia A, defined as sporadic cases (n=58) and hereditary cases (n=51), were enrolled for genotypic analysis. Results: Intron 22 inversion was prominently found in 34 sporadic (58.6%) and 27 hereditary (51.9%) cases. The screening for intron 22 inversion among females without family history of hemophilia at antenatal care has been optionally suggested. A female with a positive result will undergo further prenatal diagnosis of hemophilia in her male offspring. On the contrary, a female with a negative test result remains at risk to have a hemophiliac son caused by other factor VIII gene mutations not included in the screening but the risk is not as high as intron 22 inversion. Although the screening of factor VIII mutation among females without family history of hemophilia is against the current practice, it has been initiated due to the inadequate treatment provided to patients with hemophilia in countries with limited resources. The study calculated approximately one female with intron 22 inversion would exist among 17,064 females without family history of hemophilia. The cost of screening (194,870 USD) was much less than that of treating one patient with hemophilia from birth to 40 years of age by the current regimen (378,000 USD). Conclusion: Implementing antenatal screening of intron 22 inversion among females without family history of hemophilia is optionally suggested, especially in economically less-developed countries with inadequate treatment service for patients with hemophilia.

PROC Promoter Single Nucleotide Polymorphisms Associated With Low Protein C Activity But Not Increased Risk of Thromboembolism in Pediatric Population.

Protein C (PC) deficiency, caused by mutations of the PROC gene, is a common inherited risk factor of thromboembolism (TE) among Thai people. This study aimed to investigate the association of 3 single nucleotide polymorphisms (SNPs; -1654 C/T, -1641 A/G, -1461A/T) at the PROC promoter region with PC activity and the risk of developing TE. A total of 216 patient s with TE, diagnosed at aged 0 to 20 years, and 102 healthy adults were enrolled. The SNPs were identified by Sanger sequencing. Protein C activity was measured using an automated functional clotting assay. Linear and logistic regression analyses were used to determine the association of SNPs with PC activity and the risk of TE. Patients and controls with homozygous TAA (119.6% ± 26.1%) and CGT haplotypes (102.7% ± 22.6%) had significantly lower PC activity than those with a homozygous CAA haplotype (140.4% ± 44.9%); P = .027 and .016, respectively. However, none of these haplotypes increased the risk of TE. This study suggested that the 3 PROC promoter SNPs were shown to be associated with lower PC activity but did not increase the risk of TE.

The Effect of Blood Transfusion on Growth of Patients with Hb E/ß-Thalassemia.

A retrospective evaluation of growth in 112 patients (68 males, 44 females) with Hb E (HBB: c.79G>A)/ß-thalassemia (ß-thal), classified as 88 transfusion-dependent thalassemia (TDT) and 24 non transfusion-dependent thalassemia (NTDT), is reported. Patients with TDT have received regular transfusions of red blood cells (RBCs) 15 mL/kg every 4 weeks to maintain pre transfusion hemoglobin (Hb) levels of at least 9.0 g/dL and were categorized according to age at initiation of regular RBC transfusion as subgroup 1, <4 years; subgroup 2, 4-10 years, and subgroup 3, >10 years. Iron chelation was initiated at the mean age of 7 years. The results revealed that patients in subgroups 1 and 2, receiving RBC transfusions at a young age (2.9 and 6.9 years, respectively), had normal prepubertal growth at enrollment and last follow-up. Patients in subgroup 3, with the lowest initial height Z-score of -2.10, were able to achieve comparable final adult height as those in subgroups 1 and 2. The mean final height of 21 males and 13 females with TDT at the ages of 18.9 and 18.7 years was 168.1 and 157.7 cm, respectively, which did not significantly differ from their midparental height and those with NTDT. Early initiation of optimal transfusion and iron chelation promoted normal prepubertal growth. However, delayed initiation of transfusion at age 12 years impaired prepubertal growth but they could achieve normal final adult height.