We report four sibs with Kenny-Caffey syndrome in a consanguineous Bedouin family. The first two died in the neonatal period while the remaining affected brother and sister had all the characteristic clinical, biochemical, and radiological abnormalities of the syndrome. These included severe pre-and postnatal growth retardation, cortical thickening of the tubular bones with medullary stenosis, eye abnormalities, facial dysmorphism, hypocalcaemia, and low levels of parathyroid hormone. The children also showed intracranial calcification, impaired neutrophil phagocytosis, increased proportion of B lymphocytes, reduced CD4 and CD8 subpopulations of T lymphocytes, and inhibited transformation in response to Candida antigen. Fluorescence in situ hybridisation (FISH) was applied to blood lymphocyte metaphase spreads from these two Bedouin sibs and their parents using probe D22S75 (Oncor), specific for the DiGeorge critical region on chromosome 22ql1.2. The presence of 22q11.2 haploinsufficiency was identified in the affected sibs, which was transmitted from the phenotypically normal mother. The present report widens the spectrum of CATCH 22 microdeletion to accommodate Kenny-Caffey syndrome.
We describe 2 unrelated Bedouin girls who met the criteria for the diagnosis of Kenny-Caffey syndrome. The girls had some unusual features--microcephaly and psychomotor retardation--that distinguish the Kenny-Caffey syndrome profile in Arab children from the classical Kenny-Caffey syndrome phenotype characterized by macrocephaly and normal intelligence. The 2 girls did not harbor the 22q11 microdeletion (the hallmark of the DiGeorge cluster of diseases) that we previously reported in another Bedouin family with the Kenny-Caffey syndrome (Sabry et al. J Med Genet 1998: 35(1): 31-36). This indicates considerable genetic heterogeneity for this syndrome. We also review previously reported 44 Arab/Bedouin patients with the same profile of hypoparathyroidism, short stature, seizures, mental retardation and microcephaly. Our results suggest that these patients represent an Arab variant of Kenny-Caffey syndrome with characteristic microcephaly and psychomotor retardation. We suggest that all patients with Kenny-Caffey syndrome should be investigated for the 22q11 microdeletion. Other possible genetic causes for the Kenny-Caffey syndrome or its Arab variant include chromosome 10p abnormalities.
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