Type E brachydactyly

About: Type E brachydactyly is a research topic. Over the lifetime, 11 publications have been published within this topic receiving 276 citations.

Brachydactyly and Mental Retardation: An Albright Hereditary Osteodystrophy–like Syndrome Localized to 2q37

Abstract: We report five patients with a combination of brachymetaphalangia and mental retardation, similar to that observed in Albright hereditary osteodystrophy (AHO). Four patients had cytogenetically visible de novo deletions of chromosome 2q37. The fifth patient was cytogenetically normal and had normal bioactivity of the α subunit of Gs (Gsα), the protein that is defective in AHO. In this patient, we have used a combination of highly polymorphic molecular markers and FISH to demonstrate a microdeletion at 2q37. The common region of deletion overlap involves the most telomeric 2q marker, D2S125, and extends proximally for a maximum distance of 17.6 cM. We suggest this represents a consistent phenotype associated with some deletions at 2q37 and that genes important for skeletal and neurodevelopment lie within this region. Screening for deletions at this locus should be considered in individuals with brachymetaphalangia and mental retardation. Furthermore, 2q37 represents a candidate region for type E brachydactyly.

Classification and identification of inherited brachydactylies

Abstract: A search for patterns of malformation in the brachydactylies has resulted in new ways to identify the different types. Type A-1 can be characterised by a proportionate reduction of the middle phalanges. Type B is thought to be an amputation-like defect. In type C the fourth middle phalanx is usually the longest, and type E (Riccardi and Holmes, 1974) is characterised by short metacarpals and short distal phalanges. Short stature is usually present in type A-1 and type E brachydactyly (Riccardi and Holmes, 1974) and it may be present in some individuals with brachydactyly C. As short children have short hands, it is possible that in patients with very mild expressions of brachydactyly the cause of the short stature may be overlooked. It is suggested that in every child with proportionate short stature the hands should be carefully examined. If the hands are disproportionately short, if any distal creases are missing, if there is a shortening, however mild, of any finger, if any metacarpals are short, then it is important to have ϰ-rays to look for brachydactyly A-1, C, or E. Much information is still needed. It is important in future reports to have skeletal surveys, pattern profile analyses, and to note the height of children with brachydactyly C. Most interesting of all will be when fetal limbs of each type become available for study.

Dose dependent expression of HDAC4 causes variable expressivity in a novel inherited case of brachydactyly mental retardation syndrome.

Abstract: Histone deacetylase 4 (HDAC4) serves important roles in multiple human systems, including neurological, cardiac, and skeletal functions. Mutation or deletion of HDAC4 causes brachydactyly mental retardation syndrome (BDMR), a disorder that includes intellectual disability, behavioral abnormalities, autism spectrum disorder, and craniofacial and skeletal anomalies, including brachydactyly type E. We present a case of familial BDMR, including a parent with mild symptoms of the disorder and a child exhibiting a more severe phenotype. Cytogenetic testing showed a cryptic balanced translocation in the mother that resulted in a 2q37.1 monosomy and a 10q26.1 trisomy in the son. Gene expression analyses demonstrated 67% HDAC4 expression in the mother and 23% HDAC4 expression in the son relative to normal controls, lending evidence to the hypothesis that HDAC4 modulates severity of this disorder in a dosage-dependent manner.