In vivo diagnosis of Kufs' disease by extracerebral biopsies

Novel compound heterozygous mutations causing Kufs disease type B

BACKGROUND

Kufs disease type B (also termed CLN13), an adult-onset form of neuronal ceroid lipofuscinosis (NCL), is genetically heterogeneous and challenging to diagnose. Recently, mutations in cathepsin-F have been identified as the causative gene for autosomal recessive Kufs disease type B.

RESULTS

Here, we report a sporadic case of Kufs disease type B with novel compound heterozygous mutations, a novel missense mutation c.977G>T (p.C326F) and a novel nonsense mutation c.416C>A (p.S139X), in the cathepsin-F gene. The magnetic resonance imaging findings were consistent with those demonstrated in adult neuronal ceroid lipofuscinosis: diffuse cortical atrophy, mild hyperintensity and reduction of the deep white matter on T2-weighted images. A skin biopsy was negative for abnormalities.

CONCLUSIONS

Altogether, our findings broaden the mutation database in relation to the neuronal ceroid lipofuscinosis, and the clinical diagnosis of Kufs disease type B was confirmed.

Usefulness of rectal biopsy for the diagnosis of Kufs disease: a controlled study and review of the literature

BACKGROUND AND PURPOSE

Rectal biopsy is usually performed for in vivo diagnosis of Kufs disease (KD). We evaluated the usefulness of rectal biopsy in the diagnosis of such condition by comparing ultrastructural data of patients with suspicion of KD with those of control subjects. Furthermore, we reviewed literature data concerning the value of such a diagnostic procedure in the diagnosis of KD.

METHODS

Sixty-five subjects were enrolled and underwent rectal biopsy. Of these, 13 had a clinical picture in keeping with KD, whereas 52, affected by Irritable Bowel Syndrome, constituted the control group.

RESULTS

Ultrastructural analysis evidenced fingerprint (FP) inclusions in 12 subjects, 4/13 with suspicion of KD and 8/52 controls. In patients, FPs were mainly located in vascular smooth muscle cells (VSMC) while in controls they were mostly found in pericytes and VSMC. No FPs were found in one patient with genetically confirmed KD. In literature, we identified 14 KD patients who underwent rectal biopsy. In most reports, ultrastructural features were not systematically analyzed or described.

CONCLUSIONS

Fingerprints are the most common ultrastructural finding in rectal biopsy in patients with suspicion of KD. However, their presence in pericytes and VSMC is not specific for KD because they may be found in controls subjects. Our literature review revealed that data on the value of rectal biopsy in the diagnosis of KD are scarce. In light of these findings, the relevance of rectal biopsy in such condition should be re-evaluated.

Progress in neuropathology of the neuronal ceroid lipofuscinoses

Since the last, 6th, International Congress on Neuronal Ceroid-Lipofuscinoses, neuropathological advances in neuronal ceroid lipofuscinoses (NCL) have been made in several areas: (1) In adult NCL (ANCL) lipopigments have now been repeatedly confirmed to contain subunit c of mitochondrial ATP synthase and even sphingolipid activators (saposins). ANCL lipopigments have also been confirmed in extracerebral tissues including skin, skeletal muscle, and spleen, but not yet lymphocytes (2). Among circulating blood cells not only B cells and subclasses of T lymphocytes, i.e., CD4(+), CD8(+), and CD56 cells, but also monocytes have been found to contain NCL lipopigments, indicating that this precursor cell in the digesting macrophage system also has an impaired metabolic catabolism for lipopigments (3). Immunohistochemical studies indicate that microglial reaction in NCL brain is limited to resident microglia without contribution by circulating monocytes (4). The granular osmiophilic deposit (GROD) type of NCL has now been established not only in infantile, but also in late-infantile, juvenile, and protracted-juvenile NCL (5). A European Tissue Registry established within the framework of a European Concerted Action on Neuronal Ceroid-Lipofuscinosis may form the basis for additional collaborative studies on NCL, including both biopsy and autopsy tissues.