Candice Feben1, Jennifer Kromberg2, Rosalind Wainwright3, David Stones4, Chris Sutton5, Janet Poole6, Tabitha Haw1, Amanda Krause1. 1. Division of Human Genetics, National Health Laboratory Service and School of Pathology, The University of the Witwatersrand, Johannesburg, South Africa. 2. Division of Human Genetics, The University of the Witwatersrand, Johannesburg, South Africa. 3. Department of Pediatrics, Chris Hani Baragwanath Hospital and The University of the Witwatersrand, Johannesburg, South Africa. 4. Department of Pediatrics, Universitas Hospital and The University of the Free State, Bloemfontein, South Africa. 5. Department of Pediatrics, Polokwane/Mankweng Hospital Complex and The University of Limpopo, Limpopo, South Africa. 6. Department of Pediatrics, Charlotte Maxeke Johannesburg Academic Hospital and The University of the Witwatersrand, Johannesburg, South Africa.
Abstract
PURPOSE: Fanconi anemia is a genotypically and phenotypically heterogeneous condition, characterized microscopically by chromosomal instability and breakage. Affected individuals manifest growth restriction and congenital physical abnormalities; most progress to hematological disease including bone marrow aplasia. Black South African Fanconi anemia patients share a common causative founder mutation in the Fanconi G gene in 80% of cases (637_643delTACCGCC). The aim of this study was to investigate the genotype-physical phenotype correlation in a cohort of individuals homozygous for this mutation. METHODS: Thirty-five black patients were recruited from tertiary level hematology/oncology clinics in South Africa. Participants were subjected to a comprehensive clinical examination, documenting growth, congenital anomalies, and phenotypic variability. RESULTS: Descriptive statistical analysis showed significant growth abnormalities in many patients and a high frequency (97%) of skin pigmentary anomalies. Subtle anomalies of the eyes, ears, and hands occurred frequently (≥70%). Apart from malformations of the kidney (in 37%) and gastrointestinal tract (in 8.5%), congenital anomalies of other systems including the cardiovascular and central nervous systems, genitalia, and vertebrae were infrequent (<5%). CONCLUSION: The diagnosis of Fanconi anemia in black South African patients before the onset of hematological symptoms remains a clinical challenge, with the physical phenotype unlikely to be recognized by those without dysmorphology expertise.
PURPOSE: Fanconi anemia is a genotypically and phenotypically heterogeneous condition, characterized microscopically by chromosomal instability and breakage. Affected individuals manifest growth restriction and congenital physical abnormalities; most progress to hematological disease including bone marrow aplasia. Black South African Fanconi anemia patients share a common causative founder mutation in the Fanconi G gene in 80% of cases (637_643delTACCGCC). The aim of this study was to investigate the genotype-physical phenotype correlation in a cohort of individuals homozygous for this mutation. METHODS: Thirty-five black patients were recruited from tertiary level hematology/oncology clinics in South Africa. Participants were subjected to a comprehensive clinical examination, documenting growth, congenital anomalies, and phenotypic variability. RESULTS: Descriptive statistical analysis showed significant growth abnormalities in many patients and a high frequency (97%) of skin pigmentary anomalies. Subtle anomalies of the eyes, ears, and hands occurred frequently (≥70%). Apart from malformations of the kidney (in 37%) and gastrointestinal tract (in 8.5%), congenital anomalies of other systems including the cardiovascular and central nervous systems, genitalia, and vertebrae were infrequent (<5%). CONCLUSION: The diagnosis of Fanconi anemia in black South African patients before the onset of hematological symptoms remains a clinical challenge, with the physical phenotype unlikely to be recognized by those without dysmorphology expertise.