Glycosylphosphatidylinositol‐anchored proteins are involved in multiple physiological processes and the initial stage of their biosynthesis is mediated by PIGA, PIGC, PIGH, PIGP, PIGQ, PIGY, and DMP2 genes, which have been linked to a wide spectrum of phenotypes depending on the gene damaged. To date, the PIGP gene has only been related to Developmental and Epileptic Encephalopathy 55 (MIM#617599) in just seven patients. A detailed medical history was performed in two affected siblings with a multiple malformation syndrome. Genetic testing was performed using whole‐exome sequencing. One patient presented dysmorphic features, congenital anomalies, hypotonia and epileptic encephalopathy as described in PIGA, PIGQ and PIGY deficiencies. The other one was a fetus with a severe malformation disorder at 17 weeks of gestation whose pregnancy was interrupted. Both were compound heterozygous of pathogenic variants in PIGP gene: NM_153682.3:c.2 T > C(p.?) and a 136 Kb deletion (GRCh37/hg19 21q22.13(chr21:38329939‐38 466 066)×1) affecting the entire PIGP gene. Our results extend the clinical phenotype associated to PIGP gene and propose to include it as a novel cause of Multiple Congenital Anomalies‐Hypotonia‐Seizures syndrome.
Familial amyloidotic polyneuropathy is a genetically determined disease characterized by deposition of an anomalous transthyretin. A high index of suspicion is needed for this multisymptomatic and lethal disease to be diagnosed. The patient was a 70-year-old male examined due to hypesthesia in the hands and feet, plus difficulty walking. A neurophysiological study delivered the diagnosis of axonal sensorimotor polyneuropathy. He later developed cardiac symptoms and diarrhea. Urine laboratory analyses revealed a monoclonal spike of light chains (kappa). Biopsies of abdominal fat and bone marrow yielded normal results. The genetic study was compatible with a heterozygous Val30Met-transthyretin mutation. Very few case studies have described an association between familial amyloidotic polyneuropathy and monoclonal gammopathy. We stress that genetic confirmation is important regardless of the type of amyloid deposition revealed by the biopsy.
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