Nail aplasia, microcephaly, severe mental retardation and MRI abnormalities: report of two unrelated cases.

We present the clinical and laboratory features of two unrelated mentally retarded females with sporadic bilateral periventricular nodular heterotopia (BPNH), hypoplastic/absent nails and other malformative features. Clinical examination, MRI scanning, EEG recording, karyotyping and neuropsychological testing were performed. From a molecular genetic point of view, direct sequencing analysis, X-inactivation assay and telomere analysis were carried out in one patient. The two patients showed convincing similarities from clinical and neuroradiological points of view with BPNH, mental retardation, microcephaly and hypoplastic/absent nails of fingers and toes. Our two unrelated mentally retarded females may be affected by complex malformative syndromes sharing some common features such as BPNH, mental retardation and hypoplastic/absent nails. Further genetic studies are needed to better understand the pathogenetic bases of this neurological disease. These two cases widen the spectrum of BPNH-associated syndromes.