How many entities exist for the spectrum of disorders associated with brachydactyly, syndactyly, short stature, microcephaly, and intellectual disability?

Novel HOXD13 variants in syndactyly type 1b and type 1c, and a new spectrum of TP63-related disorders

Syndactyly is the most common limb defect depicting the bony and/or cutaneous fusion of digits. Syndactyly can be of various types depending on the digits involved in the fusion. To date, eight syndactyly-associated genes have been reported, of which HOXD13 and GJA1 have been explored in a few syndactyly but most of them have unknown underlying genetics. In the present study HOXD13, GJA1 and TP63 genes have been screened by resequencing in 24 unrelated sporadic cases with various syndactyly. The screening revealed two pathogenic HOXD13 variants, NM_000523:c.500 A > G [p.(Y167C)], and NM_000523:c.961 A > C [p.(T321P)] in syndactyly type 1b and type 1c, respectively. This is the first report to identify HOXD13 pathogenic variant in syndactyly type 1b and third report in syndactyly type 1c pathogenesis. Furthermore, this study also reports a TP63 pathogenic variant, NM_003722:c.953 G > A [p.(R318H)] in Ectrodactyly and Cleft lip and palate (ECLP). In conclusion, the current study expands the clinical spectrum of HOXD13 and TP63-related disorders.

The Development of Human Genetics at the National Research Centre, Cairo, Egypt: A Story of 50 Years

This article describes my experiences over more than 50 years in initiating and maintaining research on human genetics and genomics at the National Research Centre in Cairo, Egypt, from its beginnings in a small unit of human genetics to the creation of the Center of Excellence for Human Genetics. This was also the subject of a lecture I gave at the 10th Conference of the African Society of Human Genetics, held in Cairo in November 2017, after which Professor Michèle Ramsay, president of the society, suggested that I write an autobiographical article for the Annual Review of Genomics and Human Genetics. I hope that I succeeded in the difficult assignment of summarizing the efforts of a researcher from a developing country to initiate and maintain the rapidly advancing science of human genetics and genomics in my own country and make contributions to the worldwide scientific community.

Homozygous microdeletion of the ERI1 and MFHAS1 genes in a patient with intellectual disability, limb abnormalities, and cardiac malformation

A male child, born from consanguineous parents and having intellectual disability, short stature, dysmorphic facial features, synpolydactyly, and cardiac malformations is reported. Chromosomal microarray analysis showed that the patient presents with an 8p23.1 homozygous deletion, containing the microRNA miR-4660, the exoribonuclease 1 (ERI1), and malignant fibrous histiocytoma amplified sequence 1 (MFHAS1) genes. The microRNA miR-4660 has no known function. MFHAS1 is an immunomodulatory protein involved in Toll-like receptor signaling, erythropoiesis, and cancer. ERI1 is a ribonuclease involved in RNA metabolism and is required for the correct patterning of the skeleton by defining the HOXC8 expression. We discuss the involvement of these deleted genes to the patient's features and highlight differential diagnoses with syndromes implicating limb extremity abnormalities such as synpolydactyly, including the monosomy 8p.

Mosaic CREBBP mutation causes overlapping clinical features of Rubinstein-Taybi and Filippi syndromes

Rubinstein-Taybi syndrome (RTS, OMIM 180849) and Filippi syndrome (FLPIS, OMIM 272440) are both rare syndromes, with multiple congenital anomalies and intellectual deficit (MCA/ID). We present a patient with intellectual deficit, short stature, bilateral syndactyly of hands and feet, broad thumbs, ocular abnormalities, and dysmorphic facial features. These clinical features suggest both RTS and FLPIS. Initial DNA analysis of DNA isolated from blood did not identify variants to confirm either of these syndrome diagnoses. Whole-exome sequencing identified a homozygous variant in C9orf173, which was novel at the time of analysis. Further Sanger sequencing analysis of FLPIS cases tested negative for CKAP2L variants did not, however, reveal any further variants. Subsequent analysis using DNA isolated from buccal mucosa revealed a mosaic variant in CREBBP. This report highlights the importance of excluding mosaic variants in patients with a strong but atypical clinical presentation of a MCA/ID syndrome if no disease-causing variants can be detected in DNA isolated from blood samples. As the striking syndactyly observed in the present case is typical for FLPIS, we suggest CREBBP analysis in saliva samples for FLPIS syndrome cases in which no causal CKAP2L variant is detected.

Intellectual disability, unusual facial morphology and hand anomalies in sibs

Here we report on a Portuguese family with three sisters who shared moderate intellectual disability, unusual facial morphology (short palpebral fissures; broad nasal tip; thin upper and lower vermillion; broad and pointed chin) and hand anomalies in two of them (short left third and fifth right metacarpals in one case; marked syndactyly between the third and fourth fingers in another). One of the sisters had microcephaly and short stature, and the other two were obese. Obesity and somewhat similar facial features were also present in the otherwise healthy mother. Despite the overlap with several known syndromes (Albright osteodystrophy; Filippi syndrome; Rubinstein-Taybi syndrome; microdeletion 2q37), we suggest this condition is previously unreported, and most likely displays an autosomal recessive pattern of inheritance. © 2013 Wiley Periodicals, Inc.