Hereditary Hemochromatosis in an Adult Due to H63D Mutation: The Value of Estimating Iron Deposition By MRI T2* and Dissociation Between Serum Ferritin Concentration and Hepatic Iron Overload

Hereditary hemochromatosis (HH) is an autosomal recessive disorder characterized by excessive intestinal absorption of dietary iron, causing iron overload in different organs, especially the liver. Hemochromatosis may not be recognized until later in life. Patients are usually asymptomatic but may present with a variety of signs and symptoms. These include: hyper-pigmented skin, hepatomegaly, arthralgia, diabetes mellitusand/or heart failure/arrhythmia.

The risk of HH related morbidity in HFE compound homozygotes patients (H63D /H63D) is considered rare, we report a male patient with H63D mutation who developed impaired glucose tolerance, and high hepatic enzymes due to significant iron accumulation in the liver as well as Parkinsonian-like syndrome due to iron deposition in the basal ganglia.

A 40 year old Qatari male was referred for evaluation of a rise in hemoglobin and hematocrit values with normal MCV, total leucocyte and platelet counts.

The patient was asymptomatic with normal vital signs, no depigmentation or hepato-splenomegaly. Hematologic findings included a hemoglobin concentration of Hb 16.5 g/dL, hematocrit 53%, mean corpuscular volume (MCV) 93 fL/red cell, leucocyte count of 7200/ μL and a platelet count of 199000/μL. His serum ferritin was 359 μg/l ( normal values: < 336 μg/l), serum iron: 37 μmol/l ( normal values <28.6μmol/l), fasting transferrin saturation: 64% (normal < 50%).

A random glucose 6.5 and 6.4 mmol/L (normal values 5.5mmol/L ), A1C of 5,4 %, normal creatinine and electrolytes, alanine aminotransferase (ALT) of 66 U/l (normal < 40U/l), mild elevation of bilirubin 39 umol/l (normal <24umol/l), normal U&E Hepatitis B and C antibodies were negative.

OGTT revealed impaired glucose tolerance. Thyroid function, morning serum cortisol, LH and FSH and serum total testosterone concentrations were in the normal range.

A diagnosis of polycythemia vera was excluded on the basis of WHO Criteria 2008. The polymerase chain restriction assay was negative for the common mutation (C282Y) but positive for H63 D mutation.

Family screening confirmed HH in his brother (homozygous), whereas his mother, two brothers and the sister were carriers (heterozygous). His four offspring were carriers. This suggested an autosomal recessive mode of inheritance.

Conventional MRI study showed a normal liver size with diffuse fatty changes and focal areas of fatty sparing with some evidence of iron deposition. Whereas, T2-star (T2*) sequences showed a diffuse and significant decrease in liver signal intensity. A LIC liver concentration of 27 mg Fe/g dry wt was found (normalvalues:< 2 mg Fe/g dry wt; severe iron overload: ≥15 mg Fe/g dry wt).

No significant iron deposition in the spleen, heart or pancreas was observed.

At the age of 41 years the patient complained of tremors in both hands and arms while sitting or standing still (resting tremor) that improved with hands movements. A brain MRI revealed iron deposition in the basal ganglion. It was concluded that basal ganglionicn iron deposition mediated the neurological decline.

Currently, the transferrin saturation and serum ferritin levels are within normal.

Discussion:

This is the first case of HH secondary to H63 D among an Arab family and the first reported case of Parkinsonism tremors secondary to this mutation.

The H63D HFE variant is less frequently associated with HH, but its role in the neurodegenerative diseases has received a great attention.

An accurate evaluation of iron overload is necessary to establish the diagnosis of HH and to guide iron chelation in HH by determination of liver iron concentration (LIC) by means of T2* MRI.

Although serum ferritin concentration was only mildly increased a significant siderosis in the liver was detected by MRI T2* technique occurred. Liver siderosis was associated with mild impairment of liver function (increased serum ALT and bilirubin ).

Conclusion:

Our data further confirm that serum ferritin levels are not an accurate measure of total body iron stores in HH. Iron deposition in the liver and basal ganglion occurred despite mild elevation of ferritin. changes in basal ganglion may present by parkinsonian like tremors in these patients Use,T2* MRI should be encouraged in patients with HH for better evaluation of Iron overload and avoidance of Complications since serum ferritin can be misleading in these conditions.