A gene responsible for Ghosal hemato-diaphyseal dysplasia maps to chromosome 7q33-34

Sclerosing bone dysplasias

The group of sclerosing bone dysplasia's is a clinically and genetically heterogeneous group of rare bone disorders which, according to the latest Nosology and classification of genetic skeletal disorders (2015), can be subdivided in three subgroups; the neonatal osteosclerotic dysplasias, the osteopetroses and related disorders and the other sclerosing bone disorders. Here, we give an overview of the most important radiographic and clinical symptoms, the underlying genetic defect and potential treatment options of the different sclerosing dysplasias included in these subgroups.

Chronic steroid-response pancytopenia and increased bone density due to thromboxane synthase deficiency

Diagnosis of bone marrow failure (BMF) disorders is challenging but essential for optimal patient management. Here, we report a young adult from nonconsanguineous parents with progressive pancytopenia since childhood, bone pain, increased bone density, and haphazard ossification replacing hematopoiesis within the bone marrow. Sequencing revealed two novel biallelic variants of unknown significance within the thromboxane A synthase gene, TBXAS1 (c.266T > C; c.989T > C), bioinformatically predicted to disrupt the protein. TBXAS1 mutations result in Ghosal hematodiaphyseal dysplasia (OMIM 231095), the autosomal recessive syndrome associated with abnormal bone structure and BMF. Identification of the genetic defect prompted steroid therapy leading to resolution of symptoms.

Steroid-responsive anemia in patients of Ghosal hematodiaphyseal dysplasia: simple to diagnose and easy to treat

Ghosal hematodiaphyseal dysplasia (GHDD) is a recently recognized cause of steroid-responsive anemia. We would like to report 3 cases of GHDD who presented in early childhood with moderate to severe anemia, splenomegaly, and a hypocellular marrow with increased reticulin. They were easily diagnosed with long-bone x-rays showing diaphyseal and metaphyseal widening and loss of diaphyseal constriction. All cases dramatically responded to oral steroid and no longer needed blood transfusion. They required steroid at low doses for long term (up to 5 y). GHDD is easy to diagnose with long-bone radiography and consistently responds to steroid. It should therefore be considered as a differential diagnosis of unusual anemia in early childhood, especially in children from the Middle East or the Indian subcontinent.

Ghosal hematodiaphyseal dysplasia-a concise review including an illustrative patient

Ghosal hematodiaphyseal dysplasia is a rare autosomal recessive disorder characterized by metadiaphyseal dysplasia of long bones and defective hematopoiesis due to fibrosis or sclerosis of bone marrow. Approximately 15 cases of this entity have been reported in the literature so far. The diagnosis of this rare syndrome and its differentiation from other sclerosing bone disorders is important as correct diagnosis helps in treatment with corticosteroids, leading to considerable improvement in anemia and bony changes, negating the need for blood transfusions. We review the literature for this uncommon disorder and also present a similar case in a 21-year-old female who remained undiagnosed until this age because of unfamiliarity of clinicians with the condition.

Ghosal hematodiaphyseal dysplasia with myelofibrosis

Diaphyseal dysplasia with refractory anemia requiring blood transfusion is a relatively new entity having possible autosomal recessive inheritance. Prednisolone therapy alleviates the need for repeated transfusion. One such case is being reported here.

Report of a patient with developmental delay, hearing loss, growth retardation, and cleft lip and palate and a deletion of 7q34-36.1: review of distal 7q deletions

The use of aCGH has improved our ability to find subtle cytogenetic abnormalities as well as to find more precise information in patients with previously known abnormalities. In addition, it has allowed more specific genotype-phenotype correlation. In this report we describe a patient with a chromosomal deletion initially diagnosed with conventional cytogenetic analysis which was redemonstrated and more specifically described upon aCGH analysis. Our patient is a 12-year-old female born to a 26-year-old G1P0 mother. She was noted as a neonate to have a bilateral cleft lip and cleft palate, abnormal external ears, dysmorphic facies, and moderate to severe hearing loss. She has subsequently shown developmental delay, hyperreflexia, seizures, hyperactivity, and absence of speech. Chromosomal analysis showed deletion of 7q34q36.1. FISH studies confirmed the deletion was interstitial. Parental chromosomes were performed and did not show any cytogenetic abnormalities. aCGH was recently performed for the patient to further characterize the breakpoints of the deletion and confirmed the deletion was interstitial and of 13.2 Mb in size. Both proximal and terminal 7q deletion show a different phenotype than that of our patient. A number of patients with similar deletions have been found and while significant variability is observed, a number of findings appear to be common to deletions in this region. Therefore, we feel that distal interstitial deletions of chromosome 7q represent a recognizable phenotype and could be considered a separate deletion syndrome.

Human cytochromes P450 in health and disease

There are 18 mammalian cytochrome P450 (CYP) families, which encode 57 genes in the human genome. CYP2, CYP3 and CYP4 families contain far more genes than the other 15 families; these three families are also the ones that are dramatically larger in rodent genomes. Most (if not all) genes in the CYP1, CYP2, CYP3 and CYP4 families encode enzymes involved in eicosanoid metabolism and are inducible by various environmental stimuli (i.e. diet, chemical inducers, drugs, pheromones, etc.), whereas the other 14 gene families often have only a single member, and are rarely if ever inducible or redundant. Although the CYP2 and CYP3 families can be regarded as largely redundant and promiscuous, mutations or other defects in one or more genes of the remaining 16 gene families are primarily the ones responsible for P450-specific diseases-confirming these genes are not superfluous or promiscuous but rather are more directly involved in critical life functions. P450-mediated diseases comprise those caused by: aberrant steroidogenesis; defects in fatty acid, cholesterol and bile acid pathways; vitamin D dysregulation and retinoid (as well as putative eicosanoid) dysregulation during fertilization, implantation, embryogenesis, foetogenesis and neonatal development.

Ghosal hematodiaphyseal dysplasia: a rare cause of a myelophthisic anemia

Ghosal hematodiaphyseal dysplasia syndrome (GHDD) is a rare clinical syndrome characterized by increased bone density and a severe, myelophthisic anemia. Few cases have been reported worldwide and there are no detailed descriptions of the associated hematologic abnormalities and long-term clinical outcomes after treatment. Here, we report two siblings with GHDD who were successfully treated with chronic, low dose, corticosteroid therapy. Although GHDD is uncommon, these cases illustrate the need to consider GHDD in patients with anemia and bone dysplasia and the use of chronic, low-dose steroid therapy.

Thromboxane synthase mutations in an increased bone density disorder (Ghosal syndrome)

Studying consanguineous families with Ghosal hematodiaphyseal dysplasia syndrome (GHDD), a disorder of increased bone density, we identified mutations in TBXAS1, which encodes thromboxane synthase (TXAS). TXAS, an enzyme of the arachidonic acid cascade, produces thromboxane A(2) (TXA(2)). Platelets from subjects with GHDD showed a specific deficit in arachidonic acid-produced aggregation. We also found that TXAS and TXA(2) modulated expression of TNFSF11 and TNFRSF11B (encoding RANKL and osteoprotegerin (OPG), respectively) in primary cultured osteoblasts.