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Participant 013 headshotFemale, age 49 with muscle weakness, balance problems, clumsiness, muscle twitching (fasiculations) and cramps, abnormal heart rhythm (second-degree AV block), episodes of high potassium (hyperkalemia), restrictive lung disease, double vision (diplopia), and seizures

Date of Report November 21, 2016
The patient was in excellent health until age 45 when she started to notice muscle weakness and difficulty keeping up while playing sports. Her muscle weakness has continued to worsen and she now has balance problems, muscle twitching (fasciculations) and cramps, and difficulty with coordination. She has significant respiratory muscle weakness and requires nocturnal bi-level ventilation (BiPAP).
The patient has double vision (diplopia on lateral gaze) with weakness (opthalmoplegia) and started having seizures (left temporal lobe focus). These seizures are now controlled with carbamazepine treatment and a pacemaker.
The patient also has an abnormal heart rhythm (second-degree AV block) and had a pacemaker implanted at age 48. Based on recent imaging findings, she has probable early heart disease (cardiomyopathy).
She has been diagnosed with a potassium channel disease (channelopathy) with impaired renal excretion, and has had several episodes of extreme high potassium (hyperkalemia) with dramatic ECG changes, respiratory failure, and very low serum phosphate.
The patient also has stage 3 thyroid cancer (multifocal papillary).
  • Muscle weakness (primarily in limb-girdle distribution)
  • Protruding shoulder blades (scapular winging)
  • Muscle twitching (fasciculations) and cramps
  • Significant respiratory muscle weakness on nocturnal BiPAP
  • Abnormal muscle biopsies (abundance of “moth eaten” fibers, increased sub-sarcolemmal accumulation of mitochondria, disruption of internal architecture of type II fibers)
  • Impaired potassium excretion by the kidneys (pseudohypoaldosteronism)
  • Episodes of very high potassium (extreme hyperkalemia, to 9)
  • Balance problems, clumsiness, mild tremor, ataxia
  • Cytochrome c oxidase deficiency
  • Multiple mitochondrial DNA deletions
  • Seizures (left temporal lobe focus)
  • Double vision (diplopia on lateral gaze) with weakness (opthalmoplegia)
  • Abnormal heart rhythm (second-degree AV block)
  • Early heart disease (cardiomyopathy)(decreasing ejection fraction, severely dilated left atrium, eccentric left ventricular hypertrophy, moderate pericardial effusion, dilated main pulmonary artery)
  • Stage 3 thyroid cancer (multifocal papillary)
  • Low blood sugar (hypoglycaemia)
  • Low white blood cell levels (leukopenia)
  • Low lymphocyte levels (lymphopenia)
  • Mild anemia (likely hemolytic)
  • Cerebral folate deficiency (high levels of anti-folate antibodies)
  • Elevated IgM
  • Raynaud’s disease
  • Abnormal calcification in the kidneys (diffuse renal cortical nephrocalcinosis with retraction and scarring of cortex)
  • Low urea excretion in urine
  • High creatinine excretion in urine
  • Amino acid abnormalities (elevated amino acid levels in urine, decreased amino acid levels in cerebrospinal fluid)
Current Treatments
  • Carbamazepine – seizures
  • Florinef – high potassium
  • HCTZ – high potassium
  • Leucovorin – cerebral folate deficiency
  • Mitochondrial cocktail (coenzymeQ10, creatine, alpha lipoic acid, vitamin E) – possible mitochondrial condition
  • Omega-3 – neuro-protective effects
  • N-acetylcyteine – neuro-protective effects
  • Nocturnal bi-level ventilation (BiPAP) – restrictive lung disease
  • Plasmapheresis
  • Synthroid – post-thyroidectomy for cancer
  • Vitamin D – low vitamin D
Prior Treatments
  • Pacemaker – second-degree AV block
  • Thyroidectomy – cancer
Previously Considered Diagnoses
  • Mitochondrial disease
  • Paraneoplastic/antibody-mediated syndrome
  • Dystrophic disease/titinopathy
  • Carnitine deficiency
  • Central core disease
  • Hyperarginemia
  • Laminopathy
  • Hyperkalemic Periodic Paralysis
  • Pompe disease
Genetic Variants of Interest Clinicians and researchers are investigating the following genetic changes to see if they are causing the patient’s symptoms:
Gene Inheritance Pattern Position Transcript DNA Change Protein Change
KCND3* Autosomal dominant chr1: 112323335 NM_004980 c.1348C>T p.L450F
WNK1*/** Autosomal recessive chr12: 987490 NM_018979 c.2336C>T p.A779V
**Patient only has one variant
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