Clinical and Molecular Characteristics of Patients with Fascio-scapulo-humeral Dystrophy 1 (FSHD 1): The First Cohort Investigating the Genotype-phenotype Characteristics of FSHD 1 Patients in Turkey
Gulshan Yunisova1, Serpil Eraslan3, Sahin Avci2, İlker Eren4, Mehmet Demirhan4, Hulya Kayserili3, Piraye Oflazer5
1Neurology, Muscle Disease Center, 2Genetic Diseases Diagnosis Center, Koç University Hospital, 3Medical Genetics Department, Koc University School of Medicine (KUSoM), 4Department of Orthopedics and Traumatology, Koç University School of Medicine (KUSoM), 5Koç University Hospital, Muscle Disease Center, Koç University School of Medicine (KUSoM), Department of Neurology
Objective:

In this study, the results of the first cohort that investigated the molecular and clinical characteristics of Fascio-Scapulo-Humeral Dystrophy-1 (FSHD-1) patients in Turkey will be presented.

Background:
Due to  technical difficulties, molecular diagnosis could only be performed in  limited centers in the world so far.  As the treatment trials have accelerated lately the value of molecular diagnosis has become more important. 
Design/Methods:
Using  'Molecular Combing' (MC) method, D4Z4 repeat units (RU) of 53 patients were analyzed. FSHD clinical score (CS) test was used in clinical examination.
Results:

A reduced of D4Z4 RU (2-9) was detected in a total of 48 index patients. Then 5 more family members with reduced RU (2-9)and  FSHD phenotype were added to  study. Familial cases comprised 52% of all cases.

Group with low (0-3) CS: The RU was ≥5 (5-9) in 11 patients. The mean age at onset was 27.6±6.9 years, the most prominent initial complaints were asymmetric arm weakness and scapula dislocation (9/11), facial muscle weakness (2/11). All patients exhibited typical FSHD clinic.

Group with medium (4-10) CS: The RU was ≥2 (2-9) in 36 patients. The mean onset age was 17.4±14.3 years. Four patients had tongue weakness/atrophy, 2 patients had deltoid atrophy, and 2 patients had quadriceps muscle weakness with preserved tibialis anterior muscle.

Group with high (11-15) CS:  8 reduced RU were detected in 1 patient (6/53, 11%), remaining 5 patients showed 3-4 reduced RU. The mean onset age was 15.9±13.2 years. One patient had tongue weakness and atrophy.

Conclusions:

The correlation between the reduced number of RU and disease severity was similar to the previous reports. Additionally, the distribution of familial and de novo FSHD cases was almost equal in our study, which does not fully overlap with the literature information. In larger cohort studies, the phenotype-genotype correlation in our country will be determined more clearly.

10.1212/WNL.0000000000206152