Search

We report a case of osteoma cutis associated with a GNAS mutation in a 7-month-old boy. The patient displayed no other laboratory or physical abnormalities to suggest other GNAS-associated disorders of cutaneous ossification, including Albright's hereditary osteodystrophy or pseudohypoparathyroidism 1A, although a history of intrauterine growth restriction was troubling for progressive osseous heteroplasia. A review of the clinical and laboratory manifestations of these disorders is discussed, as well as differentiating features., (© 2012 Wiley Periodicals, Inc.)

L-2-Hydroxyglutaric aciduria (L-2-OHGA) is a rare autosomal recessive neurometabolic disease linked to chromosome 14q21.1 and is caused by mutations in the gene that most likely encodes L: -2-hydroxyglutarate dehydrogenase, which normally catalyses L: -2-hydroxyglutarate to alpha-ketoglutarate. It is characterized by progressive mental deterioration, pyramidal and cerebellar syndromes, macrocephaly and marked polycystic white-matter degeneration mainly involving frontal lobes. Brain tumours of variable nature have frequently been observed in L-2-OHGA. We report a patient affected by this disease who at the age of 20 years developed a bone tumour involving the right frontal region of the calvaria. He had first presented at the age of 10 years with psychomotor delay, clumsy gait and moderate mental impairment. Examination showed macrocephaly, cerebellar ataxia and quadripyramidal syndrome. Brain MRI showed low signal intensities on T1-weighted images and high signal intensities on T2-weighted images in cerebral subcortical white matter. Serum and urinary amino acid assay was normal. Urinary 2-hydroxyglutaric acid was 1418 mmol/mol creatinine (controls <25). Analysis of the L-2-hydroxyglutarate dehydrogenase gene revealed a homozygous mutation in exon 2 (A320G). At the age of 20 years, an osteoma of the right frontal bone was diagnosed. This finding reinforces the opinion concerning the association of L-2-OHGA and tumorigenesis and prompted us to verify the possible responsibility of some overproduced substances in this disease for the development of tumours and to look for any correlation between the type of mutation in the L-2-OHGA gene and the tumorigenic potential observed in some patients affected by this disease.

Relatives of 88 long-term survivors of childhood sarcoma were examined for the familial cancer syndrome of sarcoma, breast cancer, and other neoplasms (Li-Fraumeni syndrome). Twenty-six of 402 close relatives developed cancer (expected, 23.8), including breast cancer in four mothers (expected, 3.1). Two sarcoma probands who developed second malignant tumors have multiple relatives with cancer and might have an inherited predisposition. An increased cancer risk and exceptional requirement for disease screening appear to be confined to first-degree relatives of a small fraction of children with sarcoma, notably probands with second cancers.

Human hereditary tumors in vivo are known to show tissue specificity. Increased endoreduplication with tetraploidy has been shown to occur in cultures established only from tissue containing epithelium (skin and colonic polyps) from patients with the Gardner syndrome. Cultures established from blood (short-term lymphocyte and lymphoid suspension) and connective tissue (subcutaneous tissue, lipoma, mesentery, and sebaceous cyst) from the same patients did not show increased tetraploidy. These observations demonstrated that tetraploidy as an expression of the gene for the Gardner syndrome was cell-specific in vitro and added further evidence that increased tetraploidy could be used for detection of the Gardner gene in families at risk.